1 //===-- DAGCombiner.cpp - Implement a DAG node combiner -------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Nate Begeman and is distributed under the
6 // University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass combines dag nodes to form fewer, simpler DAG nodes. It can be run
11 // both before and after the DAG is legalized.
13 // FIXME: Missing folds
14 // sdiv, udiv, srem, urem (X, const) where X is an integer can be expanded into
15 // a sequence of multiplies, shifts, and adds. This should be controlled by
16 // some kind of hint from the target that int div is expensive.
17 // various folds of mulh[s,u] by constants such as -1, powers of 2, etc.
19 // FIXME: select C, pow2, pow2 -> something smart
20 // FIXME: trunc(select X, Y, Z) -> select X, trunc(Y), trunc(Z)
21 // FIXME: Dead stores -> nuke
22 // FIXME: shr X, (and Y,31) -> shr X, Y (TRICKY!)
23 // FIXME: mul (x, const) -> shifts + adds
24 // FIXME: undef values
25 // FIXME: make truncate see through SIGN_EXTEND and AND
26 // FIXME: divide by zero is currently left unfolded. do we want to turn this
28 // FIXME: select ne (select cc, 1, 0), 0, true, false -> select cc, true, false
30 //===----------------------------------------------------------------------===//
32 #define DEBUG_TYPE "dagcombine"
33 #include "llvm/ADT/Statistic.h"
34 #include "llvm/CodeGen/SelectionDAG.h"
35 #include "llvm/Support/Debug.h"
36 #include "llvm/Support/MathExtras.h"
37 #include "llvm/Target/TargetLowering.h"
44 Statistic<> NodesCombined ("dagcombiner", "Number of dag nodes combined");
51 // Worklist of all of the nodes that need to be simplified.
52 std::vector<SDNode*> WorkList;
54 /// AddUsersToWorkList - When an instruction is simplified, add all users of
55 /// the instruction to the work lists because they might get more simplified
58 void AddUsersToWorkList(SDNode *N) {
59 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
61 WorkList.push_back(*UI);
64 /// removeFromWorkList - remove all instances of N from the worklist.
66 void removeFromWorkList(SDNode *N) {
67 WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N),
72 void AddToWorkList(SDNode *N) {
73 WorkList.push_back(N);
76 SDOperand CombineTo(SDNode *N, const std::vector<SDOperand> &To) {
78 DEBUG(std::cerr << "\nReplacing "; N->dump();
79 std::cerr << "\nWith: "; To[0].Val->dump(&DAG);
80 std::cerr << " and " << To.size()-1 << " other values\n");
81 std::vector<SDNode*> NowDead;
82 DAG.ReplaceAllUsesWith(N, To, &NowDead);
84 // Push the new nodes and any users onto the worklist
85 for (unsigned i = 0, e = To.size(); i != e; ++i) {
86 WorkList.push_back(To[i].Val);
87 AddUsersToWorkList(To[i].Val);
90 // Nodes can end up on the worklist more than once. Make sure we do
91 // not process a node that has been replaced.
92 removeFromWorkList(N);
93 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
94 removeFromWorkList(NowDead[i]);
96 // Finally, since the node is now dead, remove it from the graph.
98 return SDOperand(N, 0);
101 SDOperand CombineTo(SDNode *N, SDOperand Res) {
102 std::vector<SDOperand> To;
104 return CombineTo(N, To);
107 SDOperand CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1) {
108 std::vector<SDOperand> To;
111 return CombineTo(N, To);
115 /// SimplifyDemandedBits - Check the specified integer node value to see if
116 /// it can be simplified or if things it uses can be simplified by bit
117 /// propagation. If so, return true.
118 bool SimplifyDemandedBits(SDOperand Op) {
119 TargetLowering::TargetLoweringOpt TLO(DAG);
120 uint64_t KnownZero, KnownOne;
121 uint64_t Demanded = MVT::getIntVTBitMask(Op.getValueType());
122 if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO))
126 WorkList.push_back(Op.Val);
128 // Replace the old value with the new one.
130 DEBUG(std::cerr << "\nReplacing "; TLO.Old.Val->dump();
131 std::cerr << "\nWith: "; TLO.New.Val->dump(&DAG));
133 std::vector<SDNode*> NowDead;
134 DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, NowDead);
136 // Push the new node and any (possibly new) users onto the worklist.
137 WorkList.push_back(TLO.New.Val);
138 AddUsersToWorkList(TLO.New.Val);
140 // Nodes can end up on the worklist more than once. Make sure we do
141 // not process a node that has been replaced.
142 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
143 removeFromWorkList(NowDead[i]);
145 // Finally, if the node is now dead, remove it from the graph. The node
146 // may not be dead if the replacement process recursively simplified to
147 // something else needing this node.
148 if (TLO.Old.Val->use_empty()) {
149 removeFromWorkList(TLO.Old.Val);
150 DAG.DeleteNode(TLO.Old.Val);
155 /// visit - call the node-specific routine that knows how to fold each
156 /// particular type of node.
157 SDOperand visit(SDNode *N);
159 // Visitation implementation - Implement dag node combining for different
160 // node types. The semantics are as follows:
162 // SDOperand.Val == 0 - No change was made
163 // SDOperand.Val == N - N was replaced, is dead, and is already handled.
164 // otherwise - N should be replaced by the returned Operand.
166 SDOperand visitTokenFactor(SDNode *N);
167 SDOperand visitADD(SDNode *N);
168 SDOperand visitSUB(SDNode *N);
169 SDOperand visitMUL(SDNode *N);
170 SDOperand visitSDIV(SDNode *N);
171 SDOperand visitUDIV(SDNode *N);
172 SDOperand visitSREM(SDNode *N);
173 SDOperand visitUREM(SDNode *N);
174 SDOperand visitMULHU(SDNode *N);
175 SDOperand visitMULHS(SDNode *N);
176 SDOperand visitAND(SDNode *N);
177 SDOperand visitOR(SDNode *N);
178 SDOperand visitXOR(SDNode *N);
179 SDOperand visitVBinOp(SDNode *N, ISD::NodeType IntOp, ISD::NodeType FPOp);
180 SDOperand visitSHL(SDNode *N);
181 SDOperand visitSRA(SDNode *N);
182 SDOperand visitSRL(SDNode *N);
183 SDOperand visitCTLZ(SDNode *N);
184 SDOperand visitCTTZ(SDNode *N);
185 SDOperand visitCTPOP(SDNode *N);
186 SDOperand visitSELECT(SDNode *N);
187 SDOperand visitSELECT_CC(SDNode *N);
188 SDOperand visitSETCC(SDNode *N);
189 SDOperand visitSIGN_EXTEND(SDNode *N);
190 SDOperand visitZERO_EXTEND(SDNode *N);
191 SDOperand visitANY_EXTEND(SDNode *N);
192 SDOperand visitSIGN_EXTEND_INREG(SDNode *N);
193 SDOperand visitTRUNCATE(SDNode *N);
194 SDOperand visitBIT_CONVERT(SDNode *N);
195 SDOperand visitVBIT_CONVERT(SDNode *N);
196 SDOperand visitFADD(SDNode *N);
197 SDOperand visitFSUB(SDNode *N);
198 SDOperand visitFMUL(SDNode *N);
199 SDOperand visitFDIV(SDNode *N);
200 SDOperand visitFREM(SDNode *N);
201 SDOperand visitFCOPYSIGN(SDNode *N);
202 SDOperand visitSINT_TO_FP(SDNode *N);
203 SDOperand visitUINT_TO_FP(SDNode *N);
204 SDOperand visitFP_TO_SINT(SDNode *N);
205 SDOperand visitFP_TO_UINT(SDNode *N);
206 SDOperand visitFP_ROUND(SDNode *N);
207 SDOperand visitFP_ROUND_INREG(SDNode *N);
208 SDOperand visitFP_EXTEND(SDNode *N);
209 SDOperand visitFNEG(SDNode *N);
210 SDOperand visitFABS(SDNode *N);
211 SDOperand visitBRCOND(SDNode *N);
212 SDOperand visitBR_CC(SDNode *N);
213 SDOperand visitLOAD(SDNode *N);
214 SDOperand visitXEXTLOAD(SDNode *N);
215 SDOperand visitSTORE(SDNode *N);
216 SDOperand visitINSERT_VECTOR_ELT(SDNode *N);
217 SDOperand visitVINSERT_VECTOR_ELT(SDNode *N);
218 SDOperand visitVBUILD_VECTOR(SDNode *N);
219 SDOperand visitVECTOR_SHUFFLE(SDNode *N);
220 SDOperand visitVVECTOR_SHUFFLE(SDNode *N);
222 SDOperand XformToShuffleWithZero(SDNode *N);
223 SDOperand ReassociateOps(unsigned Opc, SDOperand LHS, SDOperand RHS);
225 bool SimplifySelectOps(SDNode *SELECT, SDOperand LHS, SDOperand RHS);
226 SDOperand SimplifyBinOpWithSameOpcodeHands(SDNode *N);
227 SDOperand SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2);
228 SDOperand SimplifySelectCC(SDOperand N0, SDOperand N1, SDOperand N2,
229 SDOperand N3, ISD::CondCode CC);
230 SDOperand SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1,
231 ISD::CondCode Cond, bool foldBooleans = true);
232 SDOperand ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(SDNode *, MVT::ValueType);
233 SDOperand BuildSDIV(SDNode *N);
234 SDOperand BuildUDIV(SDNode *N);
236 DAGCombiner(SelectionDAG &D)
237 : DAG(D), TLI(D.getTargetLoweringInfo()), AfterLegalize(false) {}
239 /// Run - runs the dag combiner on all nodes in the work list
240 void Run(bool RunningAfterLegalize);
244 //===----------------------------------------------------------------------===//
245 // TargetLowering::DAGCombinerInfo implementation
246 //===----------------------------------------------------------------------===//
248 void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) {
249 ((DAGCombiner*)DC)->AddToWorkList(N);
252 SDOperand TargetLowering::DAGCombinerInfo::
253 CombineTo(SDNode *N, const std::vector<SDOperand> &To) {
254 return ((DAGCombiner*)DC)->CombineTo(N, To);
257 SDOperand TargetLowering::DAGCombinerInfo::
258 CombineTo(SDNode *N, SDOperand Res) {
259 return ((DAGCombiner*)DC)->CombineTo(N, Res);
263 SDOperand TargetLowering::DAGCombinerInfo::
264 CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1) {
265 return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1);
271 //===----------------------------------------------------------------------===//
275 int64_t m; // magic number
276 int64_t s; // shift amount
280 uint64_t m; // magic number
281 int64_t a; // add indicator
282 int64_t s; // shift amount
285 /// magic - calculate the magic numbers required to codegen an integer sdiv as
286 /// a sequence of multiply and shifts. Requires that the divisor not be 0, 1,
288 static ms magic32(int32_t d) {
290 uint32_t ad, anc, delta, q1, r1, q2, r2, t;
291 const uint32_t two31 = 0x80000000U;
295 t = two31 + ((uint32_t)d >> 31);
296 anc = t - 1 - t%ad; // absolute value of nc
297 p = 31; // initialize p
298 q1 = two31/anc; // initialize q1 = 2p/abs(nc)
299 r1 = two31 - q1*anc; // initialize r1 = rem(2p,abs(nc))
300 q2 = two31/ad; // initialize q2 = 2p/abs(d)
301 r2 = two31 - q2*ad; // initialize r2 = rem(2p,abs(d))
304 q1 = 2*q1; // update q1 = 2p/abs(nc)
305 r1 = 2*r1; // update r1 = rem(2p/abs(nc))
306 if (r1 >= anc) { // must be unsigned comparison
310 q2 = 2*q2; // update q2 = 2p/abs(d)
311 r2 = 2*r2; // update r2 = rem(2p/abs(d))
312 if (r2 >= ad) { // must be unsigned comparison
317 } while (q1 < delta || (q1 == delta && r1 == 0));
319 mag.m = (int32_t)(q2 + 1); // make sure to sign extend
320 if (d < 0) mag.m = -mag.m; // resulting magic number
321 mag.s = p - 32; // resulting shift
325 /// magicu - calculate the magic numbers required to codegen an integer udiv as
326 /// a sequence of multiply, add and shifts. Requires that the divisor not be 0.
327 static mu magicu32(uint32_t d) {
329 uint32_t nc, delta, q1, r1, q2, r2;
331 magu.a = 0; // initialize "add" indicator
333 p = 31; // initialize p
334 q1 = 0x80000000/nc; // initialize q1 = 2p/nc
335 r1 = 0x80000000 - q1*nc; // initialize r1 = rem(2p,nc)
336 q2 = 0x7FFFFFFF/d; // initialize q2 = (2p-1)/d
337 r2 = 0x7FFFFFFF - q2*d; // initialize r2 = rem((2p-1),d)
340 if (r1 >= nc - r1 ) {
341 q1 = 2*q1 + 1; // update q1
342 r1 = 2*r1 - nc; // update r1
345 q1 = 2*q1; // update q1
346 r1 = 2*r1; // update r1
348 if (r2 + 1 >= d - r2) {
349 if (q2 >= 0x7FFFFFFF) magu.a = 1;
350 q2 = 2*q2 + 1; // update q2
351 r2 = 2*r2 + 1 - d; // update r2
354 if (q2 >= 0x80000000) magu.a = 1;
355 q2 = 2*q2; // update q2
356 r2 = 2*r2 + 1; // update r2
359 } while (p < 64 && (q1 < delta || (q1 == delta && r1 == 0)));
360 magu.m = q2 + 1; // resulting magic number
361 magu.s = p - 32; // resulting shift
365 /// magic - calculate the magic numbers required to codegen an integer sdiv as
366 /// a sequence of multiply and shifts. Requires that the divisor not be 0, 1,
368 static ms magic64(int64_t d) {
370 uint64_t ad, anc, delta, q1, r1, q2, r2, t;
371 const uint64_t two63 = 9223372036854775808ULL; // 2^63
374 ad = d >= 0 ? d : -d;
375 t = two63 + ((uint64_t)d >> 63);
376 anc = t - 1 - t%ad; // absolute value of nc
377 p = 63; // initialize p
378 q1 = two63/anc; // initialize q1 = 2p/abs(nc)
379 r1 = two63 - q1*anc; // initialize r1 = rem(2p,abs(nc))
380 q2 = two63/ad; // initialize q2 = 2p/abs(d)
381 r2 = two63 - q2*ad; // initialize r2 = rem(2p,abs(d))
384 q1 = 2*q1; // update q1 = 2p/abs(nc)
385 r1 = 2*r1; // update r1 = rem(2p/abs(nc))
386 if (r1 >= anc) { // must be unsigned comparison
390 q2 = 2*q2; // update q2 = 2p/abs(d)
391 r2 = 2*r2; // update r2 = rem(2p/abs(d))
392 if (r2 >= ad) { // must be unsigned comparison
397 } while (q1 < delta || (q1 == delta && r1 == 0));
400 if (d < 0) mag.m = -mag.m; // resulting magic number
401 mag.s = p - 64; // resulting shift
405 /// magicu - calculate the magic numbers required to codegen an integer udiv as
406 /// a sequence of multiply, add and shifts. Requires that the divisor not be 0.
407 static mu magicu64(uint64_t d)
410 uint64_t nc, delta, q1, r1, q2, r2;
412 magu.a = 0; // initialize "add" indicator
414 p = 63; // initialize p
415 q1 = 0x8000000000000000ull/nc; // initialize q1 = 2p/nc
416 r1 = 0x8000000000000000ull - q1*nc; // initialize r1 = rem(2p,nc)
417 q2 = 0x7FFFFFFFFFFFFFFFull/d; // initialize q2 = (2p-1)/d
418 r2 = 0x7FFFFFFFFFFFFFFFull - q2*d; // initialize r2 = rem((2p-1),d)
421 if (r1 >= nc - r1 ) {
422 q1 = 2*q1 + 1; // update q1
423 r1 = 2*r1 - nc; // update r1
426 q1 = 2*q1; // update q1
427 r1 = 2*r1; // update r1
429 if (r2 + 1 >= d - r2) {
430 if (q2 >= 0x7FFFFFFFFFFFFFFFull) magu.a = 1;
431 q2 = 2*q2 + 1; // update q2
432 r2 = 2*r2 + 1 - d; // update r2
435 if (q2 >= 0x8000000000000000ull) magu.a = 1;
436 q2 = 2*q2; // update q2
437 r2 = 2*r2 + 1; // update r2
440 } while (p < 64 && (q1 < delta || (q1 == delta && r1 == 0)));
441 magu.m = q2 + 1; // resulting magic number
442 magu.s = p - 64; // resulting shift
446 // isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc
447 // that selects between the values 1 and 0, making it equivalent to a setcc.
448 // Also, set the incoming LHS, RHS, and CC references to the appropriate
449 // nodes based on the type of node we are checking. This simplifies life a
450 // bit for the callers.
451 static bool isSetCCEquivalent(SDOperand N, SDOperand &LHS, SDOperand &RHS,
453 if (N.getOpcode() == ISD::SETCC) {
454 LHS = N.getOperand(0);
455 RHS = N.getOperand(1);
456 CC = N.getOperand(2);
459 if (N.getOpcode() == ISD::SELECT_CC &&
460 N.getOperand(2).getOpcode() == ISD::Constant &&
461 N.getOperand(3).getOpcode() == ISD::Constant &&
462 cast<ConstantSDNode>(N.getOperand(2))->getValue() == 1 &&
463 cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) {
464 LHS = N.getOperand(0);
465 RHS = N.getOperand(1);
466 CC = N.getOperand(4);
472 // isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only
473 // one use. If this is true, it allows the users to invert the operation for
474 // free when it is profitable to do so.
475 static bool isOneUseSetCC(SDOperand N) {
476 SDOperand N0, N1, N2;
477 if (isSetCCEquivalent(N, N0, N1, N2) && N.Val->hasOneUse())
482 // FIXME: This should probably go in the ISD class rather than being duplicated
484 static bool isCommutativeBinOp(unsigned Opcode) {
490 case ISD::XOR: return true;
491 default: return false; // FIXME: Need commutative info for user ops!
495 SDOperand DAGCombiner::ReassociateOps(unsigned Opc, SDOperand N0, SDOperand N1){
496 MVT::ValueType VT = N0.getValueType();
497 // reassoc. (op (op x, c1), y) -> (op (op x, y), c1) iff x+c1 has one use
498 // reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2))
499 if (N0.getOpcode() == Opc && isa<ConstantSDNode>(N0.getOperand(1))) {
500 if (isa<ConstantSDNode>(N1)) {
501 SDOperand OpNode = DAG.getNode(Opc, VT, N0.getOperand(1), N1);
502 AddToWorkList(OpNode.Val);
503 return DAG.getNode(Opc, VT, OpNode, N0.getOperand(0));
504 } else if (N0.hasOneUse()) {
505 SDOperand OpNode = DAG.getNode(Opc, VT, N0.getOperand(0), N1);
506 AddToWorkList(OpNode.Val);
507 return DAG.getNode(Opc, VT, OpNode, N0.getOperand(1));
510 // reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one use
511 // reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2))
512 if (N1.getOpcode() == Opc && isa<ConstantSDNode>(N1.getOperand(1))) {
513 if (isa<ConstantSDNode>(N0)) {
514 SDOperand OpNode = DAG.getNode(Opc, VT, N1.getOperand(1), N0);
515 AddToWorkList(OpNode.Val);
516 return DAG.getNode(Opc, VT, OpNode, N1.getOperand(0));
517 } else if (N1.hasOneUse()) {
518 SDOperand OpNode = DAG.getNode(Opc, VT, N1.getOperand(0), N0);
519 AddToWorkList(OpNode.Val);
520 return DAG.getNode(Opc, VT, OpNode, N1.getOperand(1));
526 void DAGCombiner::Run(bool RunningAfterLegalize) {
527 // set the instance variable, so that the various visit routines may use it.
528 AfterLegalize = RunningAfterLegalize;
530 // Add all the dag nodes to the worklist.
531 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
532 E = DAG.allnodes_end(); I != E; ++I)
533 WorkList.push_back(I);
535 // Create a dummy node (which is not added to allnodes), that adds a reference
536 // to the root node, preventing it from being deleted, and tracking any
537 // changes of the root.
538 HandleSDNode Dummy(DAG.getRoot());
541 /// DagCombineInfo - Expose the DAG combiner to the target combiner impls.
542 TargetLowering::DAGCombinerInfo
543 DagCombineInfo(DAG, !RunningAfterLegalize, this);
545 // while the worklist isn't empty, inspect the node on the end of it and
546 // try and combine it.
547 while (!WorkList.empty()) {
548 SDNode *N = WorkList.back();
551 // If N has no uses, it is dead. Make sure to revisit all N's operands once
552 // N is deleted from the DAG, since they too may now be dead or may have a
553 // reduced number of uses, allowing other xforms.
554 if (N->use_empty() && N != &Dummy) {
555 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
556 WorkList.push_back(N->getOperand(i).Val);
558 removeFromWorkList(N);
563 SDOperand RV = visit(N);
565 // If nothing happened, try a target-specific DAG combine.
567 if (N->getOpcode() >= ISD::BUILTIN_OP_END ||
568 TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode()))
569 RV = TLI.PerformDAGCombine(N, DagCombineInfo);
574 // If we get back the same node we passed in, rather than a new node or
575 // zero, we know that the node must have defined multiple values and
576 // CombineTo was used. Since CombineTo takes care of the worklist
577 // mechanics for us, we have no work to do in this case.
579 DEBUG(std::cerr << "\nReplacing "; N->dump();
580 std::cerr << "\nWith: "; RV.Val->dump(&DAG);
582 std::vector<SDNode*> NowDead;
583 DAG.ReplaceAllUsesWith(N, std::vector<SDOperand>(1, RV), &NowDead);
585 // Push the new node and any users onto the worklist
586 WorkList.push_back(RV.Val);
587 AddUsersToWorkList(RV.Val);
589 // Nodes can end up on the worklist more than once. Make sure we do
590 // not process a node that has been replaced.
591 removeFromWorkList(N);
592 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
593 removeFromWorkList(NowDead[i]);
595 // Finally, since the node is now dead, remove it from the graph.
601 // If the root changed (e.g. it was a dead load, update the root).
602 DAG.setRoot(Dummy.getValue());
605 SDOperand DAGCombiner::visit(SDNode *N) {
606 switch(N->getOpcode()) {
608 case ISD::TokenFactor: return visitTokenFactor(N);
609 case ISD::ADD: return visitADD(N);
610 case ISD::SUB: return visitSUB(N);
611 case ISD::MUL: return visitMUL(N);
612 case ISD::SDIV: return visitSDIV(N);
613 case ISD::UDIV: return visitUDIV(N);
614 case ISD::SREM: return visitSREM(N);
615 case ISD::UREM: return visitUREM(N);
616 case ISD::MULHU: return visitMULHU(N);
617 case ISD::MULHS: return visitMULHS(N);
618 case ISD::AND: return visitAND(N);
619 case ISD::OR: return visitOR(N);
620 case ISD::XOR: return visitXOR(N);
621 case ISD::SHL: return visitSHL(N);
622 case ISD::SRA: return visitSRA(N);
623 case ISD::SRL: return visitSRL(N);
624 case ISD::CTLZ: return visitCTLZ(N);
625 case ISD::CTTZ: return visitCTTZ(N);
626 case ISD::CTPOP: return visitCTPOP(N);
627 case ISD::SELECT: return visitSELECT(N);
628 case ISD::SELECT_CC: return visitSELECT_CC(N);
629 case ISD::SETCC: return visitSETCC(N);
630 case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N);
631 case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N);
632 case ISD::ANY_EXTEND: return visitANY_EXTEND(N);
633 case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N);
634 case ISD::TRUNCATE: return visitTRUNCATE(N);
635 case ISD::BIT_CONVERT: return visitBIT_CONVERT(N);
636 case ISD::VBIT_CONVERT: return visitVBIT_CONVERT(N);
637 case ISD::FADD: return visitFADD(N);
638 case ISD::FSUB: return visitFSUB(N);
639 case ISD::FMUL: return visitFMUL(N);
640 case ISD::FDIV: return visitFDIV(N);
641 case ISD::FREM: return visitFREM(N);
642 case ISD::FCOPYSIGN: return visitFCOPYSIGN(N);
643 case ISD::SINT_TO_FP: return visitSINT_TO_FP(N);
644 case ISD::UINT_TO_FP: return visitUINT_TO_FP(N);
645 case ISD::FP_TO_SINT: return visitFP_TO_SINT(N);
646 case ISD::FP_TO_UINT: return visitFP_TO_UINT(N);
647 case ISD::FP_ROUND: return visitFP_ROUND(N);
648 case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N);
649 case ISD::FP_EXTEND: return visitFP_EXTEND(N);
650 case ISD::FNEG: return visitFNEG(N);
651 case ISD::FABS: return visitFABS(N);
652 case ISD::BRCOND: return visitBRCOND(N);
653 case ISD::BR_CC: return visitBR_CC(N);
654 case ISD::LOAD: return visitLOAD(N);
657 case ISD::ZEXTLOAD: return visitXEXTLOAD(N);
658 case ISD::STORE: return visitSTORE(N);
659 case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N);
660 case ISD::VINSERT_VECTOR_ELT: return visitVINSERT_VECTOR_ELT(N);
661 case ISD::VBUILD_VECTOR: return visitVBUILD_VECTOR(N);
662 case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N);
663 case ISD::VVECTOR_SHUFFLE: return visitVVECTOR_SHUFFLE(N);
664 case ISD::VADD: return visitVBinOp(N, ISD::ADD , ISD::FADD);
665 case ISD::VSUB: return visitVBinOp(N, ISD::SUB , ISD::FSUB);
666 case ISD::VMUL: return visitVBinOp(N, ISD::MUL , ISD::FMUL);
667 case ISD::VSDIV: return visitVBinOp(N, ISD::SDIV, ISD::FDIV);
668 case ISD::VUDIV: return visitVBinOp(N, ISD::UDIV, ISD::UDIV);
669 case ISD::VAND: return visitVBinOp(N, ISD::AND , ISD::AND);
670 case ISD::VOR: return visitVBinOp(N, ISD::OR , ISD::OR);
671 case ISD::VXOR: return visitVBinOp(N, ISD::XOR , ISD::XOR);
676 SDOperand DAGCombiner::visitTokenFactor(SDNode *N) {
677 std::vector<SDOperand> Ops;
678 bool Changed = false;
680 // If the token factor has two operands and one is the entry token, replace
681 // the token factor with the other operand.
682 if (N->getNumOperands() == 2) {
683 if (N->getOperand(0).getOpcode() == ISD::EntryToken ||
684 N->getOperand(0) == N->getOperand(1))
685 return N->getOperand(1);
686 if (N->getOperand(1).getOpcode() == ISD::EntryToken)
687 return N->getOperand(0);
690 // fold (tokenfactor (tokenfactor)) -> tokenfactor
691 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
692 SDOperand Op = N->getOperand(i);
693 if (Op.getOpcode() == ISD::TokenFactor && Op.hasOneUse()) {
694 AddToWorkList(Op.Val); // Remove dead node.
696 for (unsigned j = 0, e = Op.getNumOperands(); j != e; ++j)
697 Ops.push_back(Op.getOperand(j));
698 } else if (i == 0 || N->getOperand(i) != N->getOperand(i-1)) {
701 // Deleted an operand that was the same as the last one.
706 return DAG.getNode(ISD::TokenFactor, MVT::Other, Ops);
710 SDOperand DAGCombiner::visitADD(SDNode *N) {
711 SDOperand N0 = N->getOperand(0);
712 SDOperand N1 = N->getOperand(1);
713 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
714 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
715 MVT::ValueType VT = N0.getValueType();
717 // fold (add c1, c2) -> c1+c2
719 return DAG.getNode(ISD::ADD, VT, N0, N1);
720 // canonicalize constant to RHS
722 return DAG.getNode(ISD::ADD, VT, N1, N0);
723 // fold (add x, 0) -> x
724 if (N1C && N1C->isNullValue())
726 // fold ((c1-A)+c2) -> (c1+c2)-A
727 if (N1C && N0.getOpcode() == ISD::SUB)
728 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getOperand(0)))
729 return DAG.getNode(ISD::SUB, VT,
730 DAG.getConstant(N1C->getValue()+N0C->getValue(), VT),
733 SDOperand RADD = ReassociateOps(ISD::ADD, N0, N1);
736 // fold ((0-A) + B) -> B-A
737 if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) &&
738 cast<ConstantSDNode>(N0.getOperand(0))->isNullValue())
739 return DAG.getNode(ISD::SUB, VT, N1, N0.getOperand(1));
740 // fold (A + (0-B)) -> A-B
741 if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) &&
742 cast<ConstantSDNode>(N1.getOperand(0))->isNullValue())
743 return DAG.getNode(ISD::SUB, VT, N0, N1.getOperand(1));
744 // fold (A+(B-A)) -> B
745 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1))
746 return N1.getOperand(0);
748 if (!MVT::isVector(VT) && SimplifyDemandedBits(SDOperand(N, 0)))
749 return SDOperand(N, 0);
751 // fold (a+b) -> (a|b) iff a and b share no bits.
752 if (MVT::isInteger(VT) && !MVT::isVector(VT)) {
753 uint64_t LHSZero, LHSOne;
754 uint64_t RHSZero, RHSOne;
755 uint64_t Mask = MVT::getIntVTBitMask(VT);
756 TLI.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne);
758 TLI.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne);
760 // If all possibly-set bits on the LHS are clear on the RHS, return an OR.
761 // If all possibly-set bits on the RHS are clear on the LHS, return an OR.
762 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) ||
763 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask))
764 return DAG.getNode(ISD::OR, VT, N0, N1);
771 SDOperand DAGCombiner::visitSUB(SDNode *N) {
772 SDOperand N0 = N->getOperand(0);
773 SDOperand N1 = N->getOperand(1);
774 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
775 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
776 MVT::ValueType VT = N0.getValueType();
778 // fold (sub x, x) -> 0
780 return DAG.getConstant(0, N->getValueType(0));
781 // fold (sub c1, c2) -> c1-c2
783 return DAG.getNode(ISD::SUB, VT, N0, N1);
784 // fold (sub x, c) -> (add x, -c)
786 return DAG.getNode(ISD::ADD, VT, N0, DAG.getConstant(-N1C->getValue(), VT));
788 if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1)
789 return N0.getOperand(1);
791 if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1)
792 return N0.getOperand(0);
796 SDOperand DAGCombiner::visitMUL(SDNode *N) {
797 SDOperand N0 = N->getOperand(0);
798 SDOperand N1 = N->getOperand(1);
799 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
800 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
801 MVT::ValueType VT = N0.getValueType();
803 // fold (mul c1, c2) -> c1*c2
805 return DAG.getNode(ISD::MUL, VT, N0, N1);
806 // canonicalize constant to RHS
808 return DAG.getNode(ISD::MUL, VT, N1, N0);
809 // fold (mul x, 0) -> 0
810 if (N1C && N1C->isNullValue())
812 // fold (mul x, -1) -> 0-x
813 if (N1C && N1C->isAllOnesValue())
814 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0);
815 // fold (mul x, (1 << c)) -> x << c
816 if (N1C && isPowerOf2_64(N1C->getValue()))
817 return DAG.getNode(ISD::SHL, VT, N0,
818 DAG.getConstant(Log2_64(N1C->getValue()),
819 TLI.getShiftAmountTy()));
820 // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c
821 if (N1C && isPowerOf2_64(-N1C->getSignExtended())) {
822 // FIXME: If the input is something that is easily negated (e.g. a
823 // single-use add), we should put the negate there.
824 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT),
825 DAG.getNode(ISD::SHL, VT, N0,
826 DAG.getConstant(Log2_64(-N1C->getSignExtended()),
827 TLI.getShiftAmountTy())));
830 // (mul (shl X, c1), c2) -> (mul X, c2 << c1)
831 if (N1C && N0.getOpcode() == ISD::SHL &&
832 isa<ConstantSDNode>(N0.getOperand(1))) {
833 SDOperand C3 = DAG.getNode(ISD::SHL, VT, N1, N0.getOperand(1));
834 AddToWorkList(C3.Val);
835 return DAG.getNode(ISD::MUL, VT, N0.getOperand(0), C3);
838 // Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one
841 SDOperand Sh(0,0), Y(0,0);
842 // Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)).
843 if (N0.getOpcode() == ISD::SHL && isa<ConstantSDNode>(N0.getOperand(1)) &&
844 N0.Val->hasOneUse()) {
846 } else if (N1.getOpcode() == ISD::SHL &&
847 isa<ConstantSDNode>(N1.getOperand(1)) && N1.Val->hasOneUse()) {
851 SDOperand Mul = DAG.getNode(ISD::MUL, VT, Sh.getOperand(0), Y);
852 return DAG.getNode(ISD::SHL, VT, Mul, Sh.getOperand(1));
855 // fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2)
856 if (N1C && N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse() &&
857 isa<ConstantSDNode>(N0.getOperand(1))) {
858 return DAG.getNode(ISD::ADD, VT,
859 DAG.getNode(ISD::MUL, VT, N0.getOperand(0), N1),
860 DAG.getNode(ISD::MUL, VT, N0.getOperand(1), N1));
864 SDOperand RMUL = ReassociateOps(ISD::MUL, N0, N1);
870 SDOperand DAGCombiner::visitSDIV(SDNode *N) {
871 SDOperand N0 = N->getOperand(0);
872 SDOperand N1 = N->getOperand(1);
873 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
874 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
875 MVT::ValueType VT = N->getValueType(0);
877 // fold (sdiv c1, c2) -> c1/c2
878 if (N0C && N1C && !N1C->isNullValue())
879 return DAG.getNode(ISD::SDIV, VT, N0, N1);
880 // fold (sdiv X, 1) -> X
881 if (N1C && N1C->getSignExtended() == 1LL)
883 // fold (sdiv X, -1) -> 0-X
884 if (N1C && N1C->isAllOnesValue())
885 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0);
886 // If we know the sign bits of both operands are zero, strength reduce to a
887 // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2
888 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1);
889 if (TLI.MaskedValueIsZero(N1, SignBit) &&
890 TLI.MaskedValueIsZero(N0, SignBit))
891 return DAG.getNode(ISD::UDIV, N1.getValueType(), N0, N1);
892 // fold (sdiv X, pow2) -> simple ops after legalize
893 if (N1C && N1C->getValue() && !TLI.isIntDivCheap() &&
894 (isPowerOf2_64(N1C->getSignExtended()) ||
895 isPowerOf2_64(-N1C->getSignExtended()))) {
896 // If dividing by powers of two is cheap, then don't perform the following
898 if (TLI.isPow2DivCheap())
900 int64_t pow2 = N1C->getSignExtended();
901 int64_t abs2 = pow2 > 0 ? pow2 : -pow2;
902 unsigned lg2 = Log2_64(abs2);
903 // Splat the sign bit into the register
904 SDOperand SGN = DAG.getNode(ISD::SRA, VT, N0,
905 DAG.getConstant(MVT::getSizeInBits(VT)-1,
906 TLI.getShiftAmountTy()));
907 AddToWorkList(SGN.Val);
908 // Add (N0 < 0) ? abs2 - 1 : 0;
909 SDOperand SRL = DAG.getNode(ISD::SRL, VT, SGN,
910 DAG.getConstant(MVT::getSizeInBits(VT)-lg2,
911 TLI.getShiftAmountTy()));
912 SDOperand ADD = DAG.getNode(ISD::ADD, VT, N0, SRL);
913 AddToWorkList(SRL.Val);
914 AddToWorkList(ADD.Val); // Divide by pow2
915 SDOperand SRA = DAG.getNode(ISD::SRA, VT, ADD,
916 DAG.getConstant(lg2, TLI.getShiftAmountTy()));
917 // If we're dividing by a positive value, we're done. Otherwise, we must
918 // negate the result.
921 AddToWorkList(SRA.Val);
922 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), SRA);
924 // if integer divide is expensive and we satisfy the requirements, emit an
925 // alternate sequence.
926 if (N1C && (N1C->getSignExtended() < -1 || N1C->getSignExtended() > 1) &&
927 !TLI.isIntDivCheap()) {
928 SDOperand Op = BuildSDIV(N);
929 if (Op.Val) return Op;
934 SDOperand DAGCombiner::visitUDIV(SDNode *N) {
935 SDOperand N0 = N->getOperand(0);
936 SDOperand N1 = N->getOperand(1);
937 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
938 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
939 MVT::ValueType VT = N->getValueType(0);
941 // fold (udiv c1, c2) -> c1/c2
942 if (N0C && N1C && !N1C->isNullValue())
943 return DAG.getNode(ISD::UDIV, VT, N0, N1);
944 // fold (udiv x, (1 << c)) -> x >>u c
945 if (N1C && isPowerOf2_64(N1C->getValue()))
946 return DAG.getNode(ISD::SRL, VT, N0,
947 DAG.getConstant(Log2_64(N1C->getValue()),
948 TLI.getShiftAmountTy()));
949 // fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2
950 if (N1.getOpcode() == ISD::SHL) {
951 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
952 if (isPowerOf2_64(SHC->getValue())) {
953 MVT::ValueType ADDVT = N1.getOperand(1).getValueType();
954 SDOperand Add = DAG.getNode(ISD::ADD, ADDVT, N1.getOperand(1),
955 DAG.getConstant(Log2_64(SHC->getValue()),
957 AddToWorkList(Add.Val);
958 return DAG.getNode(ISD::SRL, VT, N0, Add);
962 // fold (udiv x, c) -> alternate
963 if (N1C && N1C->getValue() && !TLI.isIntDivCheap()) {
964 SDOperand Op = BuildUDIV(N);
965 if (Op.Val) return Op;
970 SDOperand DAGCombiner::visitSREM(SDNode *N) {
971 SDOperand N0 = N->getOperand(0);
972 SDOperand N1 = N->getOperand(1);
973 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
974 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
975 MVT::ValueType VT = N->getValueType(0);
977 // fold (srem c1, c2) -> c1%c2
978 if (N0C && N1C && !N1C->isNullValue())
979 return DAG.getNode(ISD::SREM, VT, N0, N1);
980 // If we know the sign bits of both operands are zero, strength reduce to a
981 // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15
982 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1);
983 if (TLI.MaskedValueIsZero(N1, SignBit) &&
984 TLI.MaskedValueIsZero(N0, SignBit))
985 return DAG.getNode(ISD::UREM, VT, N0, N1);
989 SDOperand DAGCombiner::visitUREM(SDNode *N) {
990 SDOperand N0 = N->getOperand(0);
991 SDOperand N1 = N->getOperand(1);
992 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
993 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
994 MVT::ValueType VT = N->getValueType(0);
996 // fold (urem c1, c2) -> c1%c2
997 if (N0C && N1C && !N1C->isNullValue())
998 return DAG.getNode(ISD::UREM, VT, N0, N1);
999 // fold (urem x, pow2) -> (and x, pow2-1)
1000 if (N1C && !N1C->isNullValue() && isPowerOf2_64(N1C->getValue()))
1001 return DAG.getNode(ISD::AND, VT, N0, DAG.getConstant(N1C->getValue()-1,VT));
1002 // fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1))
1003 if (N1.getOpcode() == ISD::SHL) {
1004 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
1005 if (isPowerOf2_64(SHC->getValue())) {
1006 SDOperand Add = DAG.getNode(ISD::ADD, VT, N1,DAG.getConstant(~0ULL,VT));
1007 AddToWorkList(Add.Val);
1008 return DAG.getNode(ISD::AND, VT, N0, Add);
1015 SDOperand DAGCombiner::visitMULHS(SDNode *N) {
1016 SDOperand N0 = N->getOperand(0);
1017 SDOperand N1 = N->getOperand(1);
1018 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1020 // fold (mulhs x, 0) -> 0
1021 if (N1C && N1C->isNullValue())
1023 // fold (mulhs x, 1) -> (sra x, size(x)-1)
1024 if (N1C && N1C->getValue() == 1)
1025 return DAG.getNode(ISD::SRA, N0.getValueType(), N0,
1026 DAG.getConstant(MVT::getSizeInBits(N0.getValueType())-1,
1027 TLI.getShiftAmountTy()));
1031 SDOperand DAGCombiner::visitMULHU(SDNode *N) {
1032 SDOperand N0 = N->getOperand(0);
1033 SDOperand N1 = N->getOperand(1);
1034 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1036 // fold (mulhu x, 0) -> 0
1037 if (N1C && N1C->isNullValue())
1039 // fold (mulhu x, 1) -> 0
1040 if (N1C && N1C->getValue() == 1)
1041 return DAG.getConstant(0, N0.getValueType());
1045 /// SimplifyBinOpWithSameOpcodeHands - If this is a binary operator with
1046 /// two operands of the same opcode, try to simplify it.
1047 SDOperand DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) {
1048 SDOperand N0 = N->getOperand(0), N1 = N->getOperand(1);
1049 MVT::ValueType VT = N0.getValueType();
1050 assert(N0.getOpcode() == N1.getOpcode() && "Bad input!");
1052 // For each of OP in AND/OR/XOR:
1053 // fold (OP (zext x), (zext y)) -> (zext (OP x, y))
1054 // fold (OP (sext x), (sext y)) -> (sext (OP x, y))
1055 // fold (OP (aext x), (aext y)) -> (aext (OP x, y))
1056 // fold (OP (trunc x), (trunc y)) -> (trunc (OP x, y))
1057 if ((N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND||
1058 N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::TRUNCATE) &&
1059 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) {
1060 SDOperand ORNode = DAG.getNode(N->getOpcode(),
1061 N0.getOperand(0).getValueType(),
1062 N0.getOperand(0), N1.getOperand(0));
1063 AddToWorkList(ORNode.Val);
1064 return DAG.getNode(N0.getOpcode(), VT, ORNode);
1067 // For each of OP in SHL/SRL/SRA/AND...
1068 // fold (and (OP x, z), (OP y, z)) -> (OP (and x, y), z)
1069 // fold (or (OP x, z), (OP y, z)) -> (OP (or x, y), z)
1070 // fold (xor (OP x, z), (OP y, z)) -> (OP (xor x, y), z)
1071 if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL ||
1072 N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::AND) &&
1073 N0.getOperand(1) == N1.getOperand(1)) {
1074 SDOperand ORNode = DAG.getNode(N->getOpcode(),
1075 N0.getOperand(0).getValueType(),
1076 N0.getOperand(0), N1.getOperand(0));
1077 AddToWorkList(ORNode.Val);
1078 return DAG.getNode(N0.getOpcode(), VT, ORNode, N0.getOperand(1));
1084 SDOperand DAGCombiner::visitAND(SDNode *N) {
1085 SDOperand N0 = N->getOperand(0);
1086 SDOperand N1 = N->getOperand(1);
1087 SDOperand LL, LR, RL, RR, CC0, CC1;
1088 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1089 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1090 MVT::ValueType VT = N1.getValueType();
1091 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1093 // fold (and c1, c2) -> c1&c2
1095 return DAG.getNode(ISD::AND, VT, N0, N1);
1096 // canonicalize constant to RHS
1098 return DAG.getNode(ISD::AND, VT, N1, N0);
1099 // fold (and x, -1) -> x
1100 if (N1C && N1C->isAllOnesValue())
1102 // if (and x, c) is known to be zero, return 0
1103 if (N1C && TLI.MaskedValueIsZero(SDOperand(N, 0), MVT::getIntVTBitMask(VT)))
1104 return DAG.getConstant(0, VT);
1106 SDOperand RAND = ReassociateOps(ISD::AND, N0, N1);
1109 // fold (and (or x, 0xFFFF), 0xFF) -> 0xFF
1110 if (N1C && N0.getOpcode() == ISD::OR)
1111 if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
1112 if ((ORI->getValue() & N1C->getValue()) == N1C->getValue())
1114 // fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits.
1115 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) {
1116 unsigned InMask = MVT::getIntVTBitMask(N0.getOperand(0).getValueType());
1117 if (TLI.MaskedValueIsZero(N0.getOperand(0),
1118 ~N1C->getValue() & InMask)) {
1119 SDOperand Zext = DAG.getNode(ISD::ZERO_EXTEND, N0.getValueType(),
1122 // Replace uses of the AND with uses of the Zero extend node.
1125 // We actually want to replace all uses of the any_extend with the
1126 // zero_extend, to avoid duplicating things. This will later cause this
1127 // AND to be folded.
1128 CombineTo(N0.Val, Zext);
1129 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1132 // fold (and (setcc x), (setcc y)) -> (setcc (and x, y))
1133 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
1134 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
1135 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
1137 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
1138 MVT::isInteger(LL.getValueType())) {
1139 // fold (X == 0) & (Y == 0) -> (X|Y == 0)
1140 if (cast<ConstantSDNode>(LR)->getValue() == 0 && Op1 == ISD::SETEQ) {
1141 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
1142 AddToWorkList(ORNode.Val);
1143 return DAG.getSetCC(VT, ORNode, LR, Op1);
1145 // fold (X == -1) & (Y == -1) -> (X&Y == -1)
1146 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) {
1147 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL);
1148 AddToWorkList(ANDNode.Val);
1149 return DAG.getSetCC(VT, ANDNode, LR, Op1);
1151 // fold (X > -1) & (Y > -1) -> (X|Y > -1)
1152 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) {
1153 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
1154 AddToWorkList(ORNode.Val);
1155 return DAG.getSetCC(VT, ORNode, LR, Op1);
1158 // canonicalize equivalent to ll == rl
1159 if (LL == RR && LR == RL) {
1160 Op1 = ISD::getSetCCSwappedOperands(Op1);
1163 if (LL == RL && LR == RR) {
1164 bool isInteger = MVT::isInteger(LL.getValueType());
1165 ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger);
1166 if (Result != ISD::SETCC_INVALID)
1167 return DAG.getSetCC(N0.getValueType(), LL, LR, Result);
1171 // Simplify: and (op x...), (op y...) -> (op (and x, y))
1172 if (N0.getOpcode() == N1.getOpcode()) {
1173 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N);
1174 if (Tmp.Val) return Tmp;
1177 // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1)
1178 // fold (and (sra)) -> (and (srl)) when possible.
1179 if (!MVT::isVector(VT) &&
1180 SimplifyDemandedBits(SDOperand(N, 0)))
1181 return SDOperand(N, 0);
1182 // fold (zext_inreg (extload x)) -> (zextload x)
1183 if (N0.getOpcode() == ISD::EXTLOAD) {
1184 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
1185 // If we zero all the possible extended bits, then we can turn this into
1186 // a zextload if we are running before legalize or the operation is legal.
1187 if (TLI.MaskedValueIsZero(N1, ~0ULL << MVT::getSizeInBits(EVT)) &&
1188 (!AfterLegalize || TLI.isOperationLegal(ISD::ZEXTLOAD, EVT))) {
1189 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
1190 N0.getOperand(1), N0.getOperand(2),
1193 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1194 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1197 // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use
1198 if (N0.getOpcode() == ISD::SEXTLOAD && N0.hasOneUse()) {
1199 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
1200 // If we zero all the possible extended bits, then we can turn this into
1201 // a zextload if we are running before legalize or the operation is legal.
1202 if (TLI.MaskedValueIsZero(N1, ~0ULL << MVT::getSizeInBits(EVT)) &&
1203 (!AfterLegalize || TLI.isOperationLegal(ISD::ZEXTLOAD, EVT))) {
1204 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
1205 N0.getOperand(1), N0.getOperand(2),
1208 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1209 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1213 // fold (and (load x), 255) -> (zextload x, i8)
1214 // fold (and (extload x, i16), 255) -> (zextload x, i8)
1216 (N0.getOpcode() == ISD::LOAD || N0.getOpcode() == ISD::EXTLOAD ||
1217 N0.getOpcode() == ISD::ZEXTLOAD) &&
1219 MVT::ValueType EVT, LoadedVT;
1220 if (N1C->getValue() == 255)
1222 else if (N1C->getValue() == 65535)
1224 else if (N1C->getValue() == ~0U)
1229 LoadedVT = N0.getOpcode() == ISD::LOAD ? VT :
1230 cast<VTSDNode>(N0.getOperand(3))->getVT();
1231 if (EVT != MVT::Other && LoadedVT > EVT &&
1232 (!AfterLegalize || TLI.isOperationLegal(ISD::ZEXTLOAD, EVT))) {
1233 MVT::ValueType PtrType = N0.getOperand(1).getValueType();
1234 // For big endian targets, we need to add an offset to the pointer to load
1235 // the correct bytes. For little endian systems, we merely need to read
1236 // fewer bytes from the same pointer.
1238 (MVT::getSizeInBits(LoadedVT) - MVT::getSizeInBits(EVT)) / 8;
1239 SDOperand NewPtr = N0.getOperand(1);
1240 if (!TLI.isLittleEndian())
1241 NewPtr = DAG.getNode(ISD::ADD, PtrType, NewPtr,
1242 DAG.getConstant(PtrOff, PtrType));
1243 AddToWorkList(NewPtr.Val);
1245 DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0), NewPtr,
1246 N0.getOperand(2), EVT);
1248 CombineTo(N0.Val, Load, Load.getValue(1));
1249 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1256 SDOperand DAGCombiner::visitOR(SDNode *N) {
1257 SDOperand N0 = N->getOperand(0);
1258 SDOperand N1 = N->getOperand(1);
1259 SDOperand LL, LR, RL, RR, CC0, CC1;
1260 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1261 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1262 MVT::ValueType VT = N1.getValueType();
1263 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1265 // fold (or c1, c2) -> c1|c2
1267 return DAG.getNode(ISD::OR, VT, N0, N1);
1268 // canonicalize constant to RHS
1270 return DAG.getNode(ISD::OR, VT, N1, N0);
1271 // fold (or x, 0) -> x
1272 if (N1C && N1C->isNullValue())
1274 // fold (or x, -1) -> -1
1275 if (N1C && N1C->isAllOnesValue())
1277 // fold (or x, c) -> c iff (x & ~c) == 0
1279 TLI.MaskedValueIsZero(N0,~N1C->getValue() & (~0ULL>>(64-OpSizeInBits))))
1282 SDOperand ROR = ReassociateOps(ISD::OR, N0, N1);
1285 // Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2)
1286 if (N1C && N0.getOpcode() == ISD::AND && N0.Val->hasOneUse() &&
1287 isa<ConstantSDNode>(N0.getOperand(1))) {
1288 ConstantSDNode *C1 = cast<ConstantSDNode>(N0.getOperand(1));
1289 return DAG.getNode(ISD::AND, VT, DAG.getNode(ISD::OR, VT, N0.getOperand(0),
1291 DAG.getConstant(N1C->getValue() | C1->getValue(), VT));
1293 // fold (or (setcc x), (setcc y)) -> (setcc (or x, y))
1294 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
1295 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
1296 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
1298 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
1299 MVT::isInteger(LL.getValueType())) {
1300 // fold (X != 0) | (Y != 0) -> (X|Y != 0)
1301 // fold (X < 0) | (Y < 0) -> (X|Y < 0)
1302 if (cast<ConstantSDNode>(LR)->getValue() == 0 &&
1303 (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) {
1304 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
1305 AddToWorkList(ORNode.Val);
1306 return DAG.getSetCC(VT, ORNode, LR, Op1);
1308 // fold (X != -1) | (Y != -1) -> (X&Y != -1)
1309 // fold (X > -1) | (Y > -1) -> (X&Y > -1)
1310 if (cast<ConstantSDNode>(LR)->isAllOnesValue() &&
1311 (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) {
1312 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL);
1313 AddToWorkList(ANDNode.Val);
1314 return DAG.getSetCC(VT, ANDNode, LR, Op1);
1317 // canonicalize equivalent to ll == rl
1318 if (LL == RR && LR == RL) {
1319 Op1 = ISD::getSetCCSwappedOperands(Op1);
1322 if (LL == RL && LR == RR) {
1323 bool isInteger = MVT::isInteger(LL.getValueType());
1324 ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger);
1325 if (Result != ISD::SETCC_INVALID)
1326 return DAG.getSetCC(N0.getValueType(), LL, LR, Result);
1330 // Simplify: or (op x...), (op y...) -> (op (or x, y))
1331 if (N0.getOpcode() == N1.getOpcode()) {
1332 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N);
1333 if (Tmp.Val) return Tmp;
1336 // canonicalize shl to left side in a shl/srl pair, to match rotate
1337 if (N0.getOpcode() == ISD::SRL && N1.getOpcode() == ISD::SHL)
1339 // check for rotl, rotr
1340 if (N0.getOpcode() == ISD::SHL && N1.getOpcode() == ISD::SRL &&
1341 N0.getOperand(0) == N1.getOperand(0) &&
1342 TLI.isOperationLegal(ISD::ROTL, VT) && TLI.isTypeLegal(VT)) {
1343 // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1)
1344 if (N0.getOperand(1).getOpcode() == ISD::Constant &&
1345 N1.getOperand(1).getOpcode() == ISD::Constant) {
1346 uint64_t c1val = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1347 uint64_t c2val = cast<ConstantSDNode>(N1.getOperand(1))->getValue();
1348 if ((c1val + c2val) == OpSizeInBits)
1349 return DAG.getNode(ISD::ROTL, VT, N0.getOperand(0), N0.getOperand(1));
1351 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotl x, y)
1352 if (N1.getOperand(1).getOpcode() == ISD::SUB &&
1353 N0.getOperand(1) == N1.getOperand(1).getOperand(1))
1354 if (ConstantSDNode *SUBC =
1355 dyn_cast<ConstantSDNode>(N1.getOperand(1).getOperand(0)))
1356 if (SUBC->getValue() == OpSizeInBits)
1357 return DAG.getNode(ISD::ROTL, VT, N0.getOperand(0), N0.getOperand(1));
1358 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotr x, y)
1359 if (N0.getOperand(1).getOpcode() == ISD::SUB &&
1360 N1.getOperand(1) == N0.getOperand(1).getOperand(1))
1361 if (ConstantSDNode *SUBC =
1362 dyn_cast<ConstantSDNode>(N0.getOperand(1).getOperand(0)))
1363 if (SUBC->getValue() == OpSizeInBits) {
1364 if (TLI.isOperationLegal(ISD::ROTR, VT) && TLI.isTypeLegal(VT))
1365 return DAG.getNode(ISD::ROTR, VT, N0.getOperand(0),
1368 return DAG.getNode(ISD::ROTL, VT, N0.getOperand(0),
1375 SDOperand DAGCombiner::visitXOR(SDNode *N) {
1376 SDOperand N0 = N->getOperand(0);
1377 SDOperand N1 = N->getOperand(1);
1378 SDOperand LHS, RHS, CC;
1379 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1380 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1381 MVT::ValueType VT = N0.getValueType();
1383 // fold (xor c1, c2) -> c1^c2
1385 return DAG.getNode(ISD::XOR, VT, N0, N1);
1386 // canonicalize constant to RHS
1388 return DAG.getNode(ISD::XOR, VT, N1, N0);
1389 // fold (xor x, 0) -> x
1390 if (N1C && N1C->isNullValue())
1393 SDOperand RXOR = ReassociateOps(ISD::XOR, N0, N1);
1396 // fold !(x cc y) -> (x !cc y)
1397 if (N1C && N1C->getValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) {
1398 bool isInt = MVT::isInteger(LHS.getValueType());
1399 ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(),
1401 if (N0.getOpcode() == ISD::SETCC)
1402 return DAG.getSetCC(VT, LHS, RHS, NotCC);
1403 if (N0.getOpcode() == ISD::SELECT_CC)
1404 return DAG.getSelectCC(LHS, RHS, N0.getOperand(2),N0.getOperand(3),NotCC);
1405 assert(0 && "Unhandled SetCC Equivalent!");
1408 // fold !(x or y) -> (!x and !y) iff x or y are setcc
1409 if (N1C && N1C->getValue() == 1 &&
1410 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
1411 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1);
1412 if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) {
1413 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
1414 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS
1415 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS
1416 AddToWorkList(LHS.Val); AddToWorkList(RHS.Val);
1417 return DAG.getNode(NewOpcode, VT, LHS, RHS);
1420 // fold !(x or y) -> (!x and !y) iff x or y are constants
1421 if (N1C && N1C->isAllOnesValue() &&
1422 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
1423 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1);
1424 if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) {
1425 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
1426 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS
1427 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS
1428 AddToWorkList(LHS.Val); AddToWorkList(RHS.Val);
1429 return DAG.getNode(NewOpcode, VT, LHS, RHS);
1432 // fold (xor (xor x, c1), c2) -> (xor x, c1^c2)
1433 if (N1C && N0.getOpcode() == ISD::XOR) {
1434 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
1435 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
1437 return DAG.getNode(ISD::XOR, VT, N0.getOperand(1),
1438 DAG.getConstant(N1C->getValue()^N00C->getValue(), VT));
1440 return DAG.getNode(ISD::XOR, VT, N0.getOperand(0),
1441 DAG.getConstant(N1C->getValue()^N01C->getValue(), VT));
1443 // fold (xor x, x) -> 0
1445 if (!MVT::isVector(VT)) {
1446 return DAG.getConstant(0, VT);
1447 } else if (!AfterLegalize || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)) {
1448 // Produce a vector of zeros.
1449 SDOperand El = DAG.getConstant(0, MVT::getVectorBaseType(VT));
1450 std::vector<SDOperand> Ops(MVT::getVectorNumElements(VT), El);
1451 return DAG.getNode(ISD::BUILD_VECTOR, VT, Ops);
1455 // Simplify: xor (op x...), (op y...) -> (op (xor x, y))
1456 if (N0.getOpcode() == N1.getOpcode()) {
1457 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N);
1458 if (Tmp.Val) return Tmp;
1461 // Simplify the expression using non-local knowledge.
1462 if (!MVT::isVector(VT) &&
1463 SimplifyDemandedBits(SDOperand(N, 0)))
1464 return SDOperand(N, 0);
1469 SDOperand DAGCombiner::visitSHL(SDNode *N) {
1470 SDOperand N0 = N->getOperand(0);
1471 SDOperand N1 = N->getOperand(1);
1472 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1473 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1474 MVT::ValueType VT = N0.getValueType();
1475 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1477 // fold (shl c1, c2) -> c1<<c2
1479 return DAG.getNode(ISD::SHL, VT, N0, N1);
1480 // fold (shl 0, x) -> 0
1481 if (N0C && N0C->isNullValue())
1483 // fold (shl x, c >= size(x)) -> undef
1484 if (N1C && N1C->getValue() >= OpSizeInBits)
1485 return DAG.getNode(ISD::UNDEF, VT);
1486 // fold (shl x, 0) -> x
1487 if (N1C && N1C->isNullValue())
1489 // if (shl x, c) is known to be zero, return 0
1490 if (TLI.MaskedValueIsZero(SDOperand(N, 0), MVT::getIntVTBitMask(VT)))
1491 return DAG.getConstant(0, VT);
1492 if (SimplifyDemandedBits(SDOperand(N, 0)))
1493 return SDOperand(N, 0);
1494 // fold (shl (shl x, c1), c2) -> 0 or (shl x, c1+c2)
1495 if (N1C && N0.getOpcode() == ISD::SHL &&
1496 N0.getOperand(1).getOpcode() == ISD::Constant) {
1497 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1498 uint64_t c2 = N1C->getValue();
1499 if (c1 + c2 > OpSizeInBits)
1500 return DAG.getConstant(0, VT);
1501 return DAG.getNode(ISD::SHL, VT, N0.getOperand(0),
1502 DAG.getConstant(c1 + c2, N1.getValueType()));
1504 // fold (shl (srl x, c1), c2) -> (shl (and x, -1 << c1), c2-c1) or
1505 // (srl (and x, -1 << c1), c1-c2)
1506 if (N1C && N0.getOpcode() == ISD::SRL &&
1507 N0.getOperand(1).getOpcode() == ISD::Constant) {
1508 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1509 uint64_t c2 = N1C->getValue();
1510 SDOperand Mask = DAG.getNode(ISD::AND, VT, N0.getOperand(0),
1511 DAG.getConstant(~0ULL << c1, VT));
1513 return DAG.getNode(ISD::SHL, VT, Mask,
1514 DAG.getConstant(c2-c1, N1.getValueType()));
1516 return DAG.getNode(ISD::SRL, VT, Mask,
1517 DAG.getConstant(c1-c2, N1.getValueType()));
1519 // fold (shl (sra x, c1), c1) -> (and x, -1 << c1)
1520 if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1))
1521 return DAG.getNode(ISD::AND, VT, N0.getOperand(0),
1522 DAG.getConstant(~0ULL << N1C->getValue(), VT));
1523 // fold (shl (add x, c1), c2) -> (add (shl x, c2), c1<<c2)
1524 if (N1C && N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse() &&
1525 isa<ConstantSDNode>(N0.getOperand(1))) {
1526 return DAG.getNode(ISD::ADD, VT,
1527 DAG.getNode(ISD::SHL, VT, N0.getOperand(0), N1),
1528 DAG.getNode(ISD::SHL, VT, N0.getOperand(1), N1));
1533 SDOperand DAGCombiner::visitSRA(SDNode *N) {
1534 SDOperand N0 = N->getOperand(0);
1535 SDOperand N1 = N->getOperand(1);
1536 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1537 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1538 MVT::ValueType VT = N0.getValueType();
1540 // fold (sra c1, c2) -> c1>>c2
1542 return DAG.getNode(ISD::SRA, VT, N0, N1);
1543 // fold (sra 0, x) -> 0
1544 if (N0C && N0C->isNullValue())
1546 // fold (sra -1, x) -> -1
1547 if (N0C && N0C->isAllOnesValue())
1549 // fold (sra x, c >= size(x)) -> undef
1550 if (N1C && N1C->getValue() >= MVT::getSizeInBits(VT))
1551 return DAG.getNode(ISD::UNDEF, VT);
1552 // fold (sra x, 0) -> x
1553 if (N1C && N1C->isNullValue())
1555 // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports
1557 if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) {
1558 unsigned LowBits = MVT::getSizeInBits(VT) - (unsigned)N1C->getValue();
1561 default: EVT = MVT::Other; break;
1562 case 1: EVT = MVT::i1; break;
1563 case 8: EVT = MVT::i8; break;
1564 case 16: EVT = MVT::i16; break;
1565 case 32: EVT = MVT::i32; break;
1567 if (EVT > MVT::Other && TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, EVT))
1568 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0),
1569 DAG.getValueType(EVT));
1572 // fold (sra (sra x, c1), c2) -> (sra x, c1+c2)
1573 if (N1C && N0.getOpcode() == ISD::SRA) {
1574 if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
1575 unsigned Sum = N1C->getValue() + C1->getValue();
1576 if (Sum >= MVT::getSizeInBits(VT)) Sum = MVT::getSizeInBits(VT)-1;
1577 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0),
1578 DAG.getConstant(Sum, N1C->getValueType(0)));
1582 // Simplify, based on bits shifted out of the LHS.
1583 if (N1C && SimplifyDemandedBits(SDOperand(N, 0)))
1584 return SDOperand(N, 0);
1587 // If the sign bit is known to be zero, switch this to a SRL.
1588 if (TLI.MaskedValueIsZero(N0, MVT::getIntVTSignBit(VT)))
1589 return DAG.getNode(ISD::SRL, VT, N0, N1);
1593 SDOperand DAGCombiner::visitSRL(SDNode *N) {
1594 SDOperand N0 = N->getOperand(0);
1595 SDOperand N1 = N->getOperand(1);
1596 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1597 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1598 MVT::ValueType VT = N0.getValueType();
1599 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1601 // fold (srl c1, c2) -> c1 >>u c2
1603 return DAG.getNode(ISD::SRL, VT, N0, N1);
1604 // fold (srl 0, x) -> 0
1605 if (N0C && N0C->isNullValue())
1607 // fold (srl x, c >= size(x)) -> undef
1608 if (N1C && N1C->getValue() >= OpSizeInBits)
1609 return DAG.getNode(ISD::UNDEF, VT);
1610 // fold (srl x, 0) -> x
1611 if (N1C && N1C->isNullValue())
1613 // if (srl x, c) is known to be zero, return 0
1614 if (N1C && TLI.MaskedValueIsZero(SDOperand(N, 0), ~0ULL >> (64-OpSizeInBits)))
1615 return DAG.getConstant(0, VT);
1616 // fold (srl (srl x, c1), c2) -> 0 or (srl x, c1+c2)
1617 if (N1C && N0.getOpcode() == ISD::SRL &&
1618 N0.getOperand(1).getOpcode() == ISD::Constant) {
1619 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1620 uint64_t c2 = N1C->getValue();
1621 if (c1 + c2 > OpSizeInBits)
1622 return DAG.getConstant(0, VT);
1623 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0),
1624 DAG.getConstant(c1 + c2, N1.getValueType()));
1627 // fold (srl (anyextend x), c) -> (anyextend (srl x, c))
1628 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) {
1629 // Shifting in all undef bits?
1630 MVT::ValueType SmallVT = N0.getOperand(0).getValueType();
1631 if (N1C->getValue() >= MVT::getSizeInBits(SmallVT))
1632 return DAG.getNode(ISD::UNDEF, VT);
1634 SDOperand SmallShift = DAG.getNode(ISD::SRL, SmallVT, N0.getOperand(0), N1);
1635 AddToWorkList(SmallShift.Val);
1636 return DAG.getNode(ISD::ANY_EXTEND, VT, SmallShift);
1639 // fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit).
1640 if (N1C && N0.getOpcode() == ISD::CTLZ &&
1641 N1C->getValue() == Log2_32(MVT::getSizeInBits(VT))) {
1642 uint64_t KnownZero, KnownOne, Mask = MVT::getIntVTBitMask(VT);
1643 TLI.ComputeMaskedBits(N0.getOperand(0), Mask, KnownZero, KnownOne);
1645 // If any of the input bits are KnownOne, then the input couldn't be all
1646 // zeros, thus the result of the srl will always be zero.
1647 if (KnownOne) return DAG.getConstant(0, VT);
1649 // If all of the bits input the to ctlz node are known to be zero, then
1650 // the result of the ctlz is "32" and the result of the shift is one.
1651 uint64_t UnknownBits = ~KnownZero & Mask;
1652 if (UnknownBits == 0) return DAG.getConstant(1, VT);
1654 // Otherwise, check to see if there is exactly one bit input to the ctlz.
1655 if ((UnknownBits & (UnknownBits-1)) == 0) {
1656 // Okay, we know that only that the single bit specified by UnknownBits
1657 // could be set on input to the CTLZ node. If this bit is set, the SRL
1658 // will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair
1659 // to an SRL,XOR pair, which is likely to simplify more.
1660 unsigned ShAmt = CountTrailingZeros_64(UnknownBits);
1661 SDOperand Op = N0.getOperand(0);
1663 Op = DAG.getNode(ISD::SRL, VT, Op,
1664 DAG.getConstant(ShAmt, TLI.getShiftAmountTy()));
1665 AddToWorkList(Op.Val);
1667 return DAG.getNode(ISD::XOR, VT, Op, DAG.getConstant(1, VT));
1674 SDOperand DAGCombiner::visitCTLZ(SDNode *N) {
1675 SDOperand N0 = N->getOperand(0);
1676 MVT::ValueType VT = N->getValueType(0);
1678 // fold (ctlz c1) -> c2
1679 if (isa<ConstantSDNode>(N0))
1680 return DAG.getNode(ISD::CTLZ, VT, N0);
1684 SDOperand DAGCombiner::visitCTTZ(SDNode *N) {
1685 SDOperand N0 = N->getOperand(0);
1686 MVT::ValueType VT = N->getValueType(0);
1688 // fold (cttz c1) -> c2
1689 if (isa<ConstantSDNode>(N0))
1690 return DAG.getNode(ISD::CTTZ, VT, N0);
1694 SDOperand DAGCombiner::visitCTPOP(SDNode *N) {
1695 SDOperand N0 = N->getOperand(0);
1696 MVT::ValueType VT = N->getValueType(0);
1698 // fold (ctpop c1) -> c2
1699 if (isa<ConstantSDNode>(N0))
1700 return DAG.getNode(ISD::CTPOP, VT, N0);
1704 SDOperand DAGCombiner::visitSELECT(SDNode *N) {
1705 SDOperand N0 = N->getOperand(0);
1706 SDOperand N1 = N->getOperand(1);
1707 SDOperand N2 = N->getOperand(2);
1708 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1709 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1710 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2);
1711 MVT::ValueType VT = N->getValueType(0);
1713 // fold select C, X, X -> X
1716 // fold select true, X, Y -> X
1717 if (N0C && !N0C->isNullValue())
1719 // fold select false, X, Y -> Y
1720 if (N0C && N0C->isNullValue())
1722 // fold select C, 1, X -> C | X
1723 if (MVT::i1 == VT && N1C && N1C->getValue() == 1)
1724 return DAG.getNode(ISD::OR, VT, N0, N2);
1725 // fold select C, 0, X -> ~C & X
1726 // FIXME: this should check for C type == X type, not i1?
1727 if (MVT::i1 == VT && N1C && N1C->isNullValue()) {
1728 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT));
1729 AddToWorkList(XORNode.Val);
1730 return DAG.getNode(ISD::AND, VT, XORNode, N2);
1732 // fold select C, X, 1 -> ~C | X
1733 if (MVT::i1 == VT && N2C && N2C->getValue() == 1) {
1734 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT));
1735 AddToWorkList(XORNode.Val);
1736 return DAG.getNode(ISD::OR, VT, XORNode, N1);
1738 // fold select C, X, 0 -> C & X
1739 // FIXME: this should check for C type == X type, not i1?
1740 if (MVT::i1 == VT && N2C && N2C->isNullValue())
1741 return DAG.getNode(ISD::AND, VT, N0, N1);
1742 // fold X ? X : Y --> X ? 1 : Y --> X | Y
1743 if (MVT::i1 == VT && N0 == N1)
1744 return DAG.getNode(ISD::OR, VT, N0, N2);
1745 // fold X ? Y : X --> X ? Y : 0 --> X & Y
1746 if (MVT::i1 == VT && N0 == N2)
1747 return DAG.getNode(ISD::AND, VT, N0, N1);
1748 // If we can fold this based on the true/false value, do so.
1749 if (SimplifySelectOps(N, N1, N2))
1751 // fold selects based on a setcc into other things, such as min/max/abs
1752 if (N0.getOpcode() == ISD::SETCC)
1754 // Check against MVT::Other for SELECT_CC, which is a workaround for targets
1755 // having to say they don't support SELECT_CC on every type the DAG knows
1756 // about, since there is no way to mark an opcode illegal at all value types
1757 if (TLI.isOperationLegal(ISD::SELECT_CC, MVT::Other))
1758 return DAG.getNode(ISD::SELECT_CC, VT, N0.getOperand(0), N0.getOperand(1),
1759 N1, N2, N0.getOperand(2));
1761 return SimplifySelect(N0, N1, N2);
1765 SDOperand DAGCombiner::visitSELECT_CC(SDNode *N) {
1766 SDOperand N0 = N->getOperand(0);
1767 SDOperand N1 = N->getOperand(1);
1768 SDOperand N2 = N->getOperand(2);
1769 SDOperand N3 = N->getOperand(3);
1770 SDOperand N4 = N->getOperand(4);
1771 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1772 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1773 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2);
1774 ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get();
1776 // Determine if the condition we're dealing with is constant
1777 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false);
1778 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val);
1780 // fold select_cc lhs, rhs, x, x, cc -> x
1784 // If we can fold this based on the true/false value, do so.
1785 if (SimplifySelectOps(N, N2, N3))
1788 // fold select_cc into other things, such as min/max/abs
1789 return SimplifySelectCC(N0, N1, N2, N3, CC);
1792 SDOperand DAGCombiner::visitSETCC(SDNode *N) {
1793 return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1),
1794 cast<CondCodeSDNode>(N->getOperand(2))->get());
1797 SDOperand DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
1798 SDOperand N0 = N->getOperand(0);
1799 MVT::ValueType VT = N->getValueType(0);
1801 // fold (sext c1) -> c1
1802 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0))
1803 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0);
1805 // fold (sext (sext x)) -> (sext x)
1806 // fold (sext (aext x)) -> (sext x)
1807 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND)
1808 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0.getOperand(0));
1810 // fold (sext (truncate x)) -> (sextinreg x) iff x size == sext size.
1811 if (N0.getOpcode() == ISD::TRUNCATE && N0.getOperand(0).getValueType() == VT&&
1813 TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, N0.getValueType())))
1814 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0),
1815 DAG.getValueType(N0.getValueType()));
1817 // fold (sext (load x)) -> (sext (truncate (sextload x)))
1818 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() &&
1819 (!AfterLegalize||TLI.isOperationLegal(ISD::SEXTLOAD, N0.getValueType()))){
1820 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1821 N0.getOperand(1), N0.getOperand(2),
1823 CombineTo(N, ExtLoad);
1824 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1825 ExtLoad.getValue(1));
1826 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1829 // fold (sext (sextload x)) -> (sext (truncate (sextload x)))
1830 // fold (sext ( extload x)) -> (sext (truncate (sextload x)))
1831 if ((N0.getOpcode() == ISD::SEXTLOAD || N0.getOpcode() == ISD::EXTLOAD) &&
1833 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
1834 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1835 N0.getOperand(1), N0.getOperand(2), EVT);
1836 CombineTo(N, ExtLoad);
1837 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1838 ExtLoad.getValue(1));
1839 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1845 SDOperand DAGCombiner::visitZERO_EXTEND(SDNode *N) {
1846 SDOperand N0 = N->getOperand(0);
1847 MVT::ValueType VT = N->getValueType(0);
1849 // fold (zext c1) -> c1
1850 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0))
1851 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0);
1852 // fold (zext (zext x)) -> (zext x)
1853 // fold (zext (aext x)) -> (zext x)
1854 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND)
1855 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0.getOperand(0));
1856 // fold (zext (truncate x)) -> (zextinreg x) iff x size == zext size.
1857 if (N0.getOpcode() == ISD::TRUNCATE && N0.getOperand(0).getValueType() == VT&&
1858 (!AfterLegalize || TLI.isOperationLegal(ISD::AND, N0.getValueType())))
1859 return DAG.getZeroExtendInReg(N0.getOperand(0), N0.getValueType());
1860 // fold (zext (load x)) -> (zext (truncate (zextload x)))
1861 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() &&
1862 (!AfterLegalize||TLI.isOperationLegal(ISD::ZEXTLOAD, N0.getValueType()))){
1863 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
1864 N0.getOperand(1), N0.getOperand(2),
1866 CombineTo(N, ExtLoad);
1867 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1868 ExtLoad.getValue(1));
1869 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1872 // fold (zext (zextload x)) -> (zext (truncate (zextload x)))
1873 // fold (zext ( extload x)) -> (zext (truncate (zextload x)))
1874 if ((N0.getOpcode() == ISD::ZEXTLOAD || N0.getOpcode() == ISD::EXTLOAD) &&
1876 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
1877 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
1878 N0.getOperand(1), N0.getOperand(2), EVT);
1879 CombineTo(N, ExtLoad);
1880 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1881 ExtLoad.getValue(1));
1882 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1887 SDOperand DAGCombiner::visitANY_EXTEND(SDNode *N) {
1888 SDOperand N0 = N->getOperand(0);
1889 MVT::ValueType VT = N->getValueType(0);
1891 // fold (aext c1) -> c1
1892 if (isa<ConstantSDNode>(N0))
1893 return DAG.getNode(ISD::ANY_EXTEND, VT, N0);
1894 // fold (aext (aext x)) -> (aext x)
1895 // fold (aext (zext x)) -> (zext x)
1896 // fold (aext (sext x)) -> (sext x)
1897 if (N0.getOpcode() == ISD::ANY_EXTEND ||
1898 N0.getOpcode() == ISD::ZERO_EXTEND ||
1899 N0.getOpcode() == ISD::SIGN_EXTEND)
1900 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0));
1902 // fold (aext (truncate x)) -> x iff x size == zext size.
1903 if (N0.getOpcode() == ISD::TRUNCATE && N0.getOperand(0).getValueType() == VT)
1904 return N0.getOperand(0);
1905 // fold (aext (load x)) -> (aext (truncate (extload x)))
1906 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() &&
1907 (!AfterLegalize||TLI.isOperationLegal(ISD::EXTLOAD, N0.getValueType()))) {
1908 SDOperand ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, N0.getOperand(0),
1909 N0.getOperand(1), N0.getOperand(2),
1911 CombineTo(N, ExtLoad);
1912 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1913 ExtLoad.getValue(1));
1914 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1917 // fold (aext (zextload x)) -> (aext (truncate (zextload x)))
1918 // fold (aext (sextload x)) -> (aext (truncate (sextload x)))
1919 // fold (aext ( extload x)) -> (aext (truncate (extload x)))
1920 if ((N0.getOpcode() == ISD::ZEXTLOAD || N0.getOpcode() == ISD::EXTLOAD ||
1921 N0.getOpcode() == ISD::SEXTLOAD) &&
1923 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
1924 SDOperand ExtLoad = DAG.getExtLoad(N0.getOpcode(), VT, N0.getOperand(0),
1925 N0.getOperand(1), N0.getOperand(2), EVT);
1926 CombineTo(N, ExtLoad);
1927 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1928 ExtLoad.getValue(1));
1929 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1935 SDOperand DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) {
1936 SDOperand N0 = N->getOperand(0);
1937 SDOperand N1 = N->getOperand(1);
1938 MVT::ValueType VT = N->getValueType(0);
1939 MVT::ValueType EVT = cast<VTSDNode>(N1)->getVT();
1940 unsigned EVTBits = MVT::getSizeInBits(EVT);
1942 // fold (sext_in_reg c1) -> c1
1943 if (isa<ConstantSDNode>(N0) || N0.getOpcode() == ISD::UNDEF)
1944 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0, N1);
1946 // If the input is already sign extended, just drop the extension.
1947 if (TLI.ComputeNumSignBits(N0) >= MVT::getSizeInBits(VT)-EVTBits+1)
1950 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2
1951 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
1952 EVT < cast<VTSDNode>(N0.getOperand(1))->getVT()) {
1953 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), N1);
1956 // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is zero
1957 if (TLI.MaskedValueIsZero(N0, 1ULL << (EVTBits-1)))
1958 return DAG.getZeroExtendInReg(N0, EVT);
1960 // fold (sext_in_reg (srl X, 24), i8) -> sra X, 24
1961 // fold (sext_in_reg (srl X, 23), i8) -> sra X, 23 iff possible.
1962 // We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above.
1963 if (N0.getOpcode() == ISD::SRL) {
1964 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
1965 if (ShAmt->getValue()+EVTBits <= MVT::getSizeInBits(VT)) {
1966 // We can turn this into an SRA iff the input to the SRL is already sign
1968 unsigned InSignBits = TLI.ComputeNumSignBits(N0.getOperand(0));
1969 if (MVT::getSizeInBits(VT)-(ShAmt->getValue()+EVTBits) < InSignBits)
1970 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0), N0.getOperand(1));
1974 // fold (sext_inreg (extload x)) -> (sextload x)
1975 if (N0.getOpcode() == ISD::EXTLOAD &&
1976 EVT == cast<VTSDNode>(N0.getOperand(3))->getVT() &&
1977 (!AfterLegalize || TLI.isOperationLegal(ISD::SEXTLOAD, EVT))) {
1978 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1979 N0.getOperand(1), N0.getOperand(2),
1981 CombineTo(N, ExtLoad);
1982 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1983 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1985 // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use
1986 if (N0.getOpcode() == ISD::ZEXTLOAD && N0.hasOneUse() &&
1987 EVT == cast<VTSDNode>(N0.getOperand(3))->getVT() &&
1988 (!AfterLegalize || TLI.isOperationLegal(ISD::SEXTLOAD, EVT))) {
1989 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1990 N0.getOperand(1), N0.getOperand(2),
1992 CombineTo(N, ExtLoad);
1993 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1994 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1999 SDOperand DAGCombiner::visitTRUNCATE(SDNode *N) {
2000 SDOperand N0 = N->getOperand(0);
2001 MVT::ValueType VT = N->getValueType(0);
2004 if (N0.getValueType() == N->getValueType(0))
2006 // fold (truncate c1) -> c1
2007 if (isa<ConstantSDNode>(N0))
2008 return DAG.getNode(ISD::TRUNCATE, VT, N0);
2009 // fold (truncate (truncate x)) -> (truncate x)
2010 if (N0.getOpcode() == ISD::TRUNCATE)
2011 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0));
2012 // fold (truncate (ext x)) -> (ext x) or (truncate x) or x
2013 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND||
2014 N0.getOpcode() == ISD::ANY_EXTEND) {
2015 if (N0.getValueType() < VT)
2016 // if the source is smaller than the dest, we still need an extend
2017 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0));
2018 else if (N0.getValueType() > VT)
2019 // if the source is larger than the dest, than we just need the truncate
2020 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0));
2022 // if the source and dest are the same type, we can drop both the extend
2024 return N0.getOperand(0);
2026 // fold (truncate (load x)) -> (smaller load x)
2027 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse()) {
2028 assert(MVT::getSizeInBits(N0.getValueType()) > MVT::getSizeInBits(VT) &&
2029 "Cannot truncate to larger type!");
2030 MVT::ValueType PtrType = N0.getOperand(1).getValueType();
2031 // For big endian targets, we need to add an offset to the pointer to load
2032 // the correct bytes. For little endian systems, we merely need to read
2033 // fewer bytes from the same pointer.
2035 (MVT::getSizeInBits(N0.getValueType()) - MVT::getSizeInBits(VT)) / 8;
2036 SDOperand NewPtr = TLI.isLittleEndian() ? N0.getOperand(1) :
2037 DAG.getNode(ISD::ADD, PtrType, N0.getOperand(1),
2038 DAG.getConstant(PtrOff, PtrType));
2039 AddToWorkList(NewPtr.Val);
2040 SDOperand Load = DAG.getLoad(VT, N0.getOperand(0), NewPtr,N0.getOperand(2));
2042 CombineTo(N0.Val, Load, Load.getValue(1));
2043 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
2048 SDOperand DAGCombiner::visitBIT_CONVERT(SDNode *N) {
2049 SDOperand N0 = N->getOperand(0);
2050 MVT::ValueType VT = N->getValueType(0);
2052 // If the input is a constant, let getNode() fold it.
2053 if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) {
2054 SDOperand Res = DAG.getNode(ISD::BIT_CONVERT, VT, N0);
2055 if (Res.Val != N) return Res;
2058 if (N0.getOpcode() == ISD::BIT_CONVERT) // conv(conv(x,t1),t2) -> conv(x,t2)
2059 return DAG.getNode(ISD::BIT_CONVERT, VT, N0.getOperand(0));
2061 // fold (conv (load x)) -> (load (conv*)x)
2062 // FIXME: These xforms need to know that the resultant load doesn't need a
2063 // higher alignment than the original!
2064 if (0 && N0.getOpcode() == ISD::LOAD && N0.hasOneUse()) {
2065 SDOperand Load = DAG.getLoad(VT, N0.getOperand(0), N0.getOperand(1),
2068 CombineTo(N0.Val, DAG.getNode(ISD::BIT_CONVERT, N0.getValueType(), Load),
2076 SDOperand DAGCombiner::visitVBIT_CONVERT(SDNode *N) {
2077 SDOperand N0 = N->getOperand(0);
2078 MVT::ValueType VT = N->getValueType(0);
2080 // If the input is a VBUILD_VECTOR with all constant elements, fold this now.
2081 // First check to see if this is all constant.
2082 if (N0.getOpcode() == ISD::VBUILD_VECTOR && N0.Val->hasOneUse() &&
2083 VT == MVT::Vector) {
2084 bool isSimple = true;
2085 for (unsigned i = 0, e = N0.getNumOperands()-2; i != e; ++i)
2086 if (N0.getOperand(i).getOpcode() != ISD::UNDEF &&
2087 N0.getOperand(i).getOpcode() != ISD::Constant &&
2088 N0.getOperand(i).getOpcode() != ISD::ConstantFP) {
2093 MVT::ValueType DestEltVT = cast<VTSDNode>(N->getOperand(2))->getVT();
2094 if (isSimple && !MVT::isVector(DestEltVT)) {
2095 return ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(N0.Val, DestEltVT);
2102 /// ConstantFoldVBIT_CONVERTofVBUILD_VECTOR - We know that BV is a vbuild_vector
2103 /// node with Constant, ConstantFP or Undef operands. DstEltVT indicates the
2104 /// destination element value type.
2105 SDOperand DAGCombiner::
2106 ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(SDNode *BV, MVT::ValueType DstEltVT) {
2107 MVT::ValueType SrcEltVT = BV->getOperand(0).getValueType();
2109 // If this is already the right type, we're done.
2110 if (SrcEltVT == DstEltVT) return SDOperand(BV, 0);
2112 unsigned SrcBitSize = MVT::getSizeInBits(SrcEltVT);
2113 unsigned DstBitSize = MVT::getSizeInBits(DstEltVT);
2115 // If this is a conversion of N elements of one type to N elements of another
2116 // type, convert each element. This handles FP<->INT cases.
2117 if (SrcBitSize == DstBitSize) {
2118 std::vector<SDOperand> Ops;
2119 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e; ++i) {
2120 Ops.push_back(DAG.getNode(ISD::BIT_CONVERT, DstEltVT, BV->getOperand(i)));
2121 AddToWorkList(Ops.back().Val);
2123 Ops.push_back(*(BV->op_end()-2)); // Add num elements.
2124 Ops.push_back(DAG.getValueType(DstEltVT));
2125 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, Ops);
2128 // Otherwise, we're growing or shrinking the elements. To avoid having to
2129 // handle annoying details of growing/shrinking FP values, we convert them to
2131 if (MVT::isFloatingPoint(SrcEltVT)) {
2132 // Convert the input float vector to a int vector where the elements are the
2134 assert((SrcEltVT == MVT::f32 || SrcEltVT == MVT::f64) && "Unknown FP VT!");
2135 MVT::ValueType IntVT = SrcEltVT == MVT::f32 ? MVT::i32 : MVT::i64;
2136 BV = ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(BV, IntVT).Val;
2140 // Now we know the input is an integer vector. If the output is a FP type,
2141 // convert to integer first, then to FP of the right size.
2142 if (MVT::isFloatingPoint(DstEltVT)) {
2143 assert((DstEltVT == MVT::f32 || DstEltVT == MVT::f64) && "Unknown FP VT!");
2144 MVT::ValueType TmpVT = DstEltVT == MVT::f32 ? MVT::i32 : MVT::i64;
2145 SDNode *Tmp = ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(BV, TmpVT).Val;
2147 // Next, convert to FP elements of the same size.
2148 return ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(Tmp, DstEltVT);
2151 // Okay, we know the src/dst types are both integers of differing types.
2152 // Handling growing first.
2153 assert(MVT::isInteger(SrcEltVT) && MVT::isInteger(DstEltVT));
2154 if (SrcBitSize < DstBitSize) {
2155 unsigned NumInputsPerOutput = DstBitSize/SrcBitSize;
2157 std::vector<SDOperand> Ops;
2158 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e;
2159 i += NumInputsPerOutput) {
2160 bool isLE = TLI.isLittleEndian();
2161 uint64_t NewBits = 0;
2162 bool EltIsUndef = true;
2163 for (unsigned j = 0; j != NumInputsPerOutput; ++j) {
2164 // Shift the previously computed bits over.
2165 NewBits <<= SrcBitSize;
2166 SDOperand Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j));
2167 if (Op.getOpcode() == ISD::UNDEF) continue;
2170 NewBits |= cast<ConstantSDNode>(Op)->getValue();
2174 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT));
2176 Ops.push_back(DAG.getConstant(NewBits, DstEltVT));
2179 Ops.push_back(DAG.getConstant(Ops.size(), MVT::i32)); // Add num elements.
2180 Ops.push_back(DAG.getValueType(DstEltVT)); // Add element size.
2181 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, Ops);
2184 // Finally, this must be the case where we are shrinking elements: each input
2185 // turns into multiple outputs.
2186 unsigned NumOutputsPerInput = SrcBitSize/DstBitSize;
2187 std::vector<SDOperand> Ops;
2188 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e; ++i) {
2189 if (BV->getOperand(i).getOpcode() == ISD::UNDEF) {
2190 for (unsigned j = 0; j != NumOutputsPerInput; ++j)
2191 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT));
2194 uint64_t OpVal = cast<ConstantSDNode>(BV->getOperand(i))->getValue();
2196 for (unsigned j = 0; j != NumOutputsPerInput; ++j) {
2197 unsigned ThisVal = OpVal & ((1ULL << DstBitSize)-1);
2198 OpVal >>= DstBitSize;
2199 Ops.push_back(DAG.getConstant(ThisVal, DstEltVT));
2202 // For big endian targets, swap the order of the pieces of each element.
2203 if (!TLI.isLittleEndian())
2204 std::reverse(Ops.end()-NumOutputsPerInput, Ops.end());
2206 Ops.push_back(DAG.getConstant(Ops.size(), MVT::i32)); // Add num elements.
2207 Ops.push_back(DAG.getValueType(DstEltVT)); // Add element size.
2208 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, Ops);
2213 SDOperand DAGCombiner::visitFADD(SDNode *N) {
2214 SDOperand N0 = N->getOperand(0);
2215 SDOperand N1 = N->getOperand(1);
2216 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2217 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2218 MVT::ValueType VT = N->getValueType(0);
2220 // fold (fadd c1, c2) -> c1+c2
2222 return DAG.getNode(ISD::FADD, VT, N0, N1);
2223 // canonicalize constant to RHS
2224 if (N0CFP && !N1CFP)
2225 return DAG.getNode(ISD::FADD, VT, N1, N0);
2226 // fold (A + (-B)) -> A-B
2227 if (N1.getOpcode() == ISD::FNEG)
2228 return DAG.getNode(ISD::FSUB, VT, N0, N1.getOperand(0));
2229 // fold ((-A) + B) -> B-A
2230 if (N0.getOpcode() == ISD::FNEG)
2231 return DAG.getNode(ISD::FSUB, VT, N1, N0.getOperand(0));
2235 SDOperand DAGCombiner::visitFSUB(SDNode *N) {
2236 SDOperand N0 = N->getOperand(0);
2237 SDOperand N1 = N->getOperand(1);
2238 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2239 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2240 MVT::ValueType VT = N->getValueType(0);
2242 // fold (fsub c1, c2) -> c1-c2
2244 return DAG.getNode(ISD::FSUB, VT, N0, N1);
2245 // fold (A-(-B)) -> A+B
2246 if (N1.getOpcode() == ISD::FNEG)
2247 return DAG.getNode(ISD::FADD, VT, N0, N1.getOperand(0));
2251 SDOperand DAGCombiner::visitFMUL(SDNode *N) {
2252 SDOperand N0 = N->getOperand(0);
2253 SDOperand N1 = N->getOperand(1);
2254 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2255 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2256 MVT::ValueType VT = N->getValueType(0);
2258 // fold (fmul c1, c2) -> c1*c2
2260 return DAG.getNode(ISD::FMUL, VT, N0, N1);
2261 // canonicalize constant to RHS
2262 if (N0CFP && !N1CFP)
2263 return DAG.getNode(ISD::FMUL, VT, N1, N0);
2264 // fold (fmul X, 2.0) -> (fadd X, X)
2265 if (N1CFP && N1CFP->isExactlyValue(+2.0))
2266 return DAG.getNode(ISD::FADD, VT, N0, N0);
2270 SDOperand DAGCombiner::visitFDIV(SDNode *N) {
2271 SDOperand N0 = N->getOperand(0);
2272 SDOperand N1 = N->getOperand(1);
2273 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2274 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2275 MVT::ValueType VT = N->getValueType(0);
2277 // fold (fdiv c1, c2) -> c1/c2
2279 return DAG.getNode(ISD::FDIV, VT, N0, N1);
2283 SDOperand DAGCombiner::visitFREM(SDNode *N) {
2284 SDOperand N0 = N->getOperand(0);
2285 SDOperand N1 = N->getOperand(1);
2286 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2287 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2288 MVT::ValueType VT = N->getValueType(0);
2290 // fold (frem c1, c2) -> fmod(c1,c2)
2292 return DAG.getNode(ISD::FREM, VT, N0, N1);
2296 SDOperand DAGCombiner::visitFCOPYSIGN(SDNode *N) {
2297 SDOperand N0 = N->getOperand(0);
2298 SDOperand N1 = N->getOperand(1);
2299 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2300 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2301 MVT::ValueType VT = N->getValueType(0);
2303 if (N0CFP && N1CFP) // Constant fold
2304 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1);
2307 // copysign(x, c1) -> fabs(x) iff ispos(c1)
2308 // copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1)
2313 u.d = N1CFP->getValue();
2315 return DAG.getNode(ISD::FABS, VT, N0);
2317 return DAG.getNode(ISD::FNEG, VT, DAG.getNode(ISD::FABS, VT, N0));
2320 // copysign(fabs(x), y) -> copysign(x, y)
2321 // copysign(fneg(x), y) -> copysign(x, y)
2322 // copysign(copysign(x,z), y) -> copysign(x, y)
2323 if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG ||
2324 N0.getOpcode() == ISD::FCOPYSIGN)
2325 return DAG.getNode(ISD::FCOPYSIGN, VT, N0.getOperand(0), N1);
2327 // copysign(x, abs(y)) -> abs(x)
2328 if (N1.getOpcode() == ISD::FABS)
2329 return DAG.getNode(ISD::FABS, VT, N0);
2331 // copysign(x, copysign(y,z)) -> copysign(x, z)
2332 if (N1.getOpcode() == ISD::FCOPYSIGN)
2333 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(1));
2335 // copysign(x, fp_extend(y)) -> copysign(x, y)
2336 // copysign(x, fp_round(y)) -> copysign(x, y)
2337 if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND)
2338 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(0));
2345 SDOperand DAGCombiner::visitSINT_TO_FP(SDNode *N) {
2346 SDOperand N0 = N->getOperand(0);
2347 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2348 MVT::ValueType VT = N->getValueType(0);
2350 // fold (sint_to_fp c1) -> c1fp
2352 return DAG.getNode(ISD::SINT_TO_FP, VT, N0);
2356 SDOperand DAGCombiner::visitUINT_TO_FP(SDNode *N) {
2357 SDOperand N0 = N->getOperand(0);
2358 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2359 MVT::ValueType VT = N->getValueType(0);
2361 // fold (uint_to_fp c1) -> c1fp
2363 return DAG.getNode(ISD::UINT_TO_FP, VT, N0);
2367 SDOperand DAGCombiner::visitFP_TO_SINT(SDNode *N) {
2368 SDOperand N0 = N->getOperand(0);
2369 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2370 MVT::ValueType VT = N->getValueType(0);
2372 // fold (fp_to_sint c1fp) -> c1
2374 return DAG.getNode(ISD::FP_TO_SINT, VT, N0);
2378 SDOperand DAGCombiner::visitFP_TO_UINT(SDNode *N) {
2379 SDOperand N0 = N->getOperand(0);
2380 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2381 MVT::ValueType VT = N->getValueType(0);
2383 // fold (fp_to_uint c1fp) -> c1
2385 return DAG.getNode(ISD::FP_TO_UINT, VT, N0);
2389 SDOperand DAGCombiner::visitFP_ROUND(SDNode *N) {
2390 SDOperand N0 = N->getOperand(0);
2391 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2392 MVT::ValueType VT = N->getValueType(0);
2394 // fold (fp_round c1fp) -> c1fp
2396 return DAG.getNode(ISD::FP_ROUND, VT, N0);
2398 // fold (fp_round (fp_extend x)) -> x
2399 if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType())
2400 return N0.getOperand(0);
2402 // fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y)
2403 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.Val->hasOneUse()) {
2404 SDOperand Tmp = DAG.getNode(ISD::FP_ROUND, VT, N0.getOperand(0));
2405 AddToWorkList(Tmp.Val);
2406 return DAG.getNode(ISD::FCOPYSIGN, VT, Tmp, N0.getOperand(1));
2412 SDOperand DAGCombiner::visitFP_ROUND_INREG(SDNode *N) {
2413 SDOperand N0 = N->getOperand(0);
2414 MVT::ValueType VT = N->getValueType(0);
2415 MVT::ValueType EVT = cast<VTSDNode>(N->getOperand(1))->getVT();
2416 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2418 // fold (fp_round_inreg c1fp) -> c1fp
2420 SDOperand Round = DAG.getConstantFP(N0CFP->getValue(), EVT);
2421 return DAG.getNode(ISD::FP_EXTEND, VT, Round);
2426 SDOperand DAGCombiner::visitFP_EXTEND(SDNode *N) {
2427 SDOperand N0 = N->getOperand(0);
2428 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2429 MVT::ValueType VT = N->getValueType(0);
2431 // fold (fp_extend c1fp) -> c1fp
2433 return DAG.getNode(ISD::FP_EXTEND, VT, N0);
2435 // fold (fpext (load x)) -> (fpext (fpround (extload x)))
2436 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() &&
2437 (!AfterLegalize||TLI.isOperationLegal(ISD::EXTLOAD, N0.getValueType()))) {
2438 SDOperand ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, N0.getOperand(0),
2439 N0.getOperand(1), N0.getOperand(2),
2441 CombineTo(N, ExtLoad);
2442 CombineTo(N0.Val, DAG.getNode(ISD::FP_ROUND, N0.getValueType(), ExtLoad),
2443 ExtLoad.getValue(1));
2444 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
2451 SDOperand DAGCombiner::visitFNEG(SDNode *N) {
2452 SDOperand N0 = N->getOperand(0);
2453 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2454 MVT::ValueType VT = N->getValueType(0);
2456 // fold (fneg c1) -> -c1
2458 return DAG.getNode(ISD::FNEG, VT, N0);
2459 // fold (fneg (sub x, y)) -> (sub y, x)
2460 if (N0.getOpcode() == ISD::SUB)
2461 return DAG.getNode(ISD::SUB, VT, N0.getOperand(1), N0.getOperand(0));
2462 // fold (fneg (fneg x)) -> x
2463 if (N0.getOpcode() == ISD::FNEG)
2464 return N0.getOperand(0);
2468 SDOperand DAGCombiner::visitFABS(SDNode *N) {
2469 SDOperand N0 = N->getOperand(0);
2470 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2471 MVT::ValueType VT = N->getValueType(0);
2473 // fold (fabs c1) -> fabs(c1)
2475 return DAG.getNode(ISD::FABS, VT, N0);
2476 // fold (fabs (fabs x)) -> (fabs x)
2477 if (N0.getOpcode() == ISD::FABS)
2478 return N->getOperand(0);
2479 // fold (fabs (fneg x)) -> (fabs x)
2480 // fold (fabs (fcopysign x, y)) -> (fabs x)
2481 if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN)
2482 return DAG.getNode(ISD::FABS, VT, N0.getOperand(0));
2487 SDOperand DAGCombiner::visitBRCOND(SDNode *N) {
2488 SDOperand Chain = N->getOperand(0);
2489 SDOperand N1 = N->getOperand(1);
2490 SDOperand N2 = N->getOperand(2);
2491 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
2493 // never taken branch, fold to chain
2494 if (N1C && N1C->isNullValue())
2496 // unconditional branch
2497 if (N1C && N1C->getValue() == 1)
2498 return DAG.getNode(ISD::BR, MVT::Other, Chain, N2);
2499 // fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal
2501 if (N1.getOpcode() == ISD::SETCC &&
2502 TLI.isOperationLegal(ISD::BR_CC, MVT::Other)) {
2503 return DAG.getNode(ISD::BR_CC, MVT::Other, Chain, N1.getOperand(2),
2504 N1.getOperand(0), N1.getOperand(1), N2);
2509 // Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB.
2511 SDOperand DAGCombiner::visitBR_CC(SDNode *N) {
2512 CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1));
2513 SDOperand CondLHS = N->getOperand(2), CondRHS = N->getOperand(3);
2515 // Use SimplifySetCC to simplify SETCC's.
2516 SDOperand Simp = SimplifySetCC(MVT::i1, CondLHS, CondRHS, CC->get(), false);
2517 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(Simp.Val);
2519 // fold br_cc true, dest -> br dest (unconditional branch)
2520 if (SCCC && SCCC->getValue())
2521 return DAG.getNode(ISD::BR, MVT::Other, N->getOperand(0),
2523 // fold br_cc false, dest -> unconditional fall through
2524 if (SCCC && SCCC->isNullValue())
2525 return N->getOperand(0);
2526 // fold to a simpler setcc
2527 if (Simp.Val && Simp.getOpcode() == ISD::SETCC)
2528 return DAG.getNode(ISD::BR_CC, MVT::Other, N->getOperand(0),
2529 Simp.getOperand(2), Simp.getOperand(0),
2530 Simp.getOperand(1), N->getOperand(4));
2534 SDOperand DAGCombiner::visitLOAD(SDNode *N) {
2535 SDOperand Chain = N->getOperand(0);
2536 SDOperand Ptr = N->getOperand(1);
2537 SDOperand SrcValue = N->getOperand(2);
2539 // If there are no uses of the loaded value, change uses of the chain value
2540 // into uses of the chain input (i.e. delete the dead load).
2541 if (N->hasNUsesOfValue(0, 0))
2542 return CombineTo(N, DAG.getNode(ISD::UNDEF, N->getValueType(0)), Chain);
2544 // If this load is directly stored, replace the load value with the stored
2546 // TODO: Handle store large -> read small portion.
2547 // TODO: Handle TRUNCSTORE/EXTLOAD
2548 if (Chain.getOpcode() == ISD::STORE && Chain.getOperand(2) == Ptr &&
2549 Chain.getOperand(1).getValueType() == N->getValueType(0))
2550 return CombineTo(N, Chain.getOperand(1), Chain);
2555 /// visitXEXTLOAD - Handle EXTLOAD/ZEXTLOAD/SEXTLOAD.
2556 SDOperand DAGCombiner::visitXEXTLOAD(SDNode *N) {
2557 SDOperand Chain = N->getOperand(0);
2558 SDOperand Ptr = N->getOperand(1);
2559 SDOperand SrcValue = N->getOperand(2);
2560 SDOperand EVT = N->getOperand(3);
2562 // If there are no uses of the loaded value, change uses of the chain value
2563 // into uses of the chain input (i.e. delete the dead load).
2564 if (N->hasNUsesOfValue(0, 0))
2565 return CombineTo(N, DAG.getNode(ISD::UNDEF, N->getValueType(0)), Chain);
2570 SDOperand DAGCombiner::visitSTORE(SDNode *N) {
2571 SDOperand Chain = N->getOperand(0);
2572 SDOperand Value = N->getOperand(1);
2573 SDOperand Ptr = N->getOperand(2);
2574 SDOperand SrcValue = N->getOperand(3);
2576 // If this is a store that kills a previous store, remove the previous store.
2577 if (Chain.getOpcode() == ISD::STORE && Chain.getOperand(2) == Ptr &&
2578 Chain.Val->hasOneUse() /* Avoid introducing DAG cycles */ &&
2579 // Make sure that these stores are the same value type:
2580 // FIXME: we really care that the second store is >= size of the first.
2581 Value.getValueType() == Chain.getOperand(1).getValueType()) {
2582 // Create a new store of Value that replaces both stores.
2583 SDNode *PrevStore = Chain.Val;
2584 if (PrevStore->getOperand(1) == Value) // Same value multiply stored.
2586 SDOperand NewStore = DAG.getNode(ISD::STORE, MVT::Other,
2587 PrevStore->getOperand(0), Value, Ptr,
2589 CombineTo(N, NewStore); // Nuke this store.
2590 CombineTo(PrevStore, NewStore); // Nuke the previous store.
2591 return SDOperand(N, 0);
2594 // If this is a store of a bit convert, store the input value.
2595 // FIXME: This needs to know that the resultant store does not need a
2596 // higher alignment than the original.
2597 if (0 && Value.getOpcode() == ISD::BIT_CONVERT)
2598 return DAG.getNode(ISD::STORE, MVT::Other, Chain, Value.getOperand(0),
2604 SDOperand DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) {
2605 SDOperand InVec = N->getOperand(0);
2606 SDOperand InVal = N->getOperand(1);
2607 SDOperand EltNo = N->getOperand(2);
2609 // If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new
2610 // vector with the inserted element.
2611 if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa<ConstantSDNode>(EltNo)) {
2612 unsigned Elt = cast<ConstantSDNode>(EltNo)->getValue();
2613 std::vector<SDOperand> Ops(InVec.Val->op_begin(), InVec.Val->op_end());
2614 if (Elt < Ops.size())
2616 return DAG.getNode(ISD::BUILD_VECTOR, InVec.getValueType(), Ops);
2622 SDOperand DAGCombiner::visitVINSERT_VECTOR_ELT(SDNode *N) {
2623 SDOperand InVec = N->getOperand(0);
2624 SDOperand InVal = N->getOperand(1);
2625 SDOperand EltNo = N->getOperand(2);
2626 SDOperand NumElts = N->getOperand(3);
2627 SDOperand EltType = N->getOperand(4);
2629 // If the invec is a VBUILD_VECTOR and if EltNo is a constant, build a new
2630 // vector with the inserted element.
2631 if (InVec.getOpcode() == ISD::VBUILD_VECTOR && isa<ConstantSDNode>(EltNo)) {
2632 unsigned Elt = cast<ConstantSDNode>(EltNo)->getValue();
2633 std::vector<SDOperand> Ops(InVec.Val->op_begin(), InVec.Val->op_end());
2634 if (Elt < Ops.size()-2)
2636 return DAG.getNode(ISD::VBUILD_VECTOR, InVec.getValueType(), Ops);
2642 SDOperand DAGCombiner::visitVBUILD_VECTOR(SDNode *N) {
2643 unsigned NumInScalars = N->getNumOperands()-2;
2644 SDOperand NumElts = N->getOperand(NumInScalars);
2645 SDOperand EltType = N->getOperand(NumInScalars+1);
2647 // Check to see if this is a VBUILD_VECTOR of a bunch of VEXTRACT_VECTOR_ELT
2648 // operations. If so, and if the EXTRACT_ELT vector inputs come from at most
2649 // two distinct vectors, turn this into a shuffle node.
2650 SDOperand VecIn1, VecIn2;
2651 for (unsigned i = 0; i != NumInScalars; ++i) {
2652 // Ignore undef inputs.
2653 if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue;
2655 // If this input is something other than a VEXTRACT_VECTOR_ELT with a
2656 // constant index, bail out.
2657 if (N->getOperand(i).getOpcode() != ISD::VEXTRACT_VECTOR_ELT ||
2658 !isa<ConstantSDNode>(N->getOperand(i).getOperand(1))) {
2659 VecIn1 = VecIn2 = SDOperand(0, 0);
2663 // If the input vector type disagrees with the result of the vbuild_vector,
2664 // we can't make a shuffle.
2665 SDOperand ExtractedFromVec = N->getOperand(i).getOperand(0);
2666 if (*(ExtractedFromVec.Val->op_end()-2) != NumElts ||
2667 *(ExtractedFromVec.Val->op_end()-1) != EltType) {
2668 VecIn1 = VecIn2 = SDOperand(0, 0);
2672 // Otherwise, remember this. We allow up to two distinct input vectors.
2673 if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2)
2676 if (VecIn1.Val == 0) {
2677 VecIn1 = ExtractedFromVec;
2678 } else if (VecIn2.Val == 0) {
2679 VecIn2 = ExtractedFromVec;
2682 VecIn1 = VecIn2 = SDOperand(0, 0);
2687 // If everything is good, we can make a shuffle operation.
2689 std::vector<SDOperand> BuildVecIndices;
2690 for (unsigned i = 0; i != NumInScalars; ++i) {
2691 if (N->getOperand(i).getOpcode() == ISD::UNDEF) {
2692 BuildVecIndices.push_back(DAG.getNode(ISD::UNDEF, MVT::i32));
2696 SDOperand Extract = N->getOperand(i);
2698 // If extracting from the first vector, just use the index directly.
2699 if (Extract.getOperand(0) == VecIn1) {
2700 BuildVecIndices.push_back(Extract.getOperand(1));
2704 // Otherwise, use InIdx + VecSize
2705 unsigned Idx = cast<ConstantSDNode>(Extract.getOperand(1))->getValue();
2706 BuildVecIndices.push_back(DAG.getConstant(Idx+NumInScalars, MVT::i32));
2709 // Add count and size info.
2710 BuildVecIndices.push_back(NumElts);
2711 BuildVecIndices.push_back(DAG.getValueType(MVT::i32));
2713 // Return the new VVECTOR_SHUFFLE node.
2714 std::vector<SDOperand> Ops;
2715 Ops.push_back(VecIn1);
2717 Ops.push_back(VecIn2);
2719 // Use an undef vbuild_vector as input for the second operand.
2720 std::vector<SDOperand> UnOps(NumInScalars,
2721 DAG.getNode(ISD::UNDEF,
2722 cast<VTSDNode>(EltType)->getVT()));
2723 UnOps.push_back(NumElts);
2724 UnOps.push_back(EltType);
2725 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, UnOps));
2726 AddToWorkList(Ops.back().Val);
2728 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR,MVT::Vector, BuildVecIndices));
2729 Ops.push_back(NumElts);
2730 Ops.push_back(EltType);
2731 return DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector, Ops);
2737 SDOperand DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) {
2738 SDOperand ShufMask = N->getOperand(2);
2739 unsigned NumElts = ShufMask.getNumOperands();
2741 // If the shuffle mask is an identity operation on the LHS, return the LHS.
2742 bool isIdentity = true;
2743 for (unsigned i = 0; i != NumElts; ++i) {
2744 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
2745 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i) {
2750 if (isIdentity) return N->getOperand(0);
2752 // If the shuffle mask is an identity operation on the RHS, return the RHS.
2754 for (unsigned i = 0; i != NumElts; ++i) {
2755 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
2756 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i+NumElts) {
2761 if (isIdentity) return N->getOperand(1);
2763 // If the LHS and the RHS are the same node, turn the RHS into an undef.
2764 if (N->getOperand(0) == N->getOperand(1)) {
2765 if (N->getOperand(0).getOpcode() == ISD::UNDEF)
2766 return DAG.getNode(ISD::UNDEF, N->getValueType(0));
2767 // Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the
2769 std::vector<SDOperand> MappedOps;
2770 for (unsigned i = 0, e = ShufMask.getNumOperands(); i != e; ++i) {
2771 if (ShufMask.getOperand(i).getOpcode() == ISD::UNDEF ||
2772 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() < NumElts) {
2773 MappedOps.push_back(ShufMask.getOperand(i));
2776 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() - NumElts;
2777 MappedOps.push_back(DAG.getConstant(NewIdx, MVT::i32));
2780 ShufMask = DAG.getNode(ISD::BUILD_VECTOR, ShufMask.getValueType(),
2782 AddToWorkList(ShufMask.Val);
2783 return DAG.getNode(ISD::VECTOR_SHUFFLE, N->getValueType(0),
2785 DAG.getNode(ISD::UNDEF, N->getValueType(0)),
2792 SDOperand DAGCombiner::visitVVECTOR_SHUFFLE(SDNode *N) {
2793 SDOperand ShufMask = N->getOperand(2);
2794 unsigned NumElts = ShufMask.getNumOperands()-2;
2796 // If the shuffle mask is an identity operation on the LHS, return the LHS.
2797 bool isIdentity = true;
2798 for (unsigned i = 0; i != NumElts; ++i) {
2799 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
2800 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i) {
2805 if (isIdentity) return N->getOperand(0);
2807 // If the shuffle mask is an identity operation on the RHS, return the RHS.
2809 for (unsigned i = 0; i != NumElts; ++i) {
2810 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
2811 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i+NumElts) {
2816 if (isIdentity) return N->getOperand(1);
2818 // If the LHS and the RHS are the same node, turn the RHS into an undef.
2819 if (N->getOperand(0) == N->getOperand(1)) {
2820 // Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the
2822 std::vector<SDOperand> MappedOps;
2823 for (unsigned i = 0; i != NumElts; ++i) {
2824 if (ShufMask.getOperand(i).getOpcode() == ISD::UNDEF ||
2825 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() < NumElts) {
2826 MappedOps.push_back(ShufMask.getOperand(i));
2829 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() - NumElts;
2830 MappedOps.push_back(DAG.getConstant(NewIdx, MVT::i32));
2833 // Add the type/#elts values.
2834 MappedOps.push_back(ShufMask.getOperand(NumElts));
2835 MappedOps.push_back(ShufMask.getOperand(NumElts+1));
2837 ShufMask = DAG.getNode(ISD::VBUILD_VECTOR, ShufMask.getValueType(),
2839 AddToWorkList(ShufMask.Val);
2841 // Build the undef vector.
2842 SDOperand UDVal = DAG.getNode(ISD::UNDEF, MappedOps[0].getValueType());
2843 for (unsigned i = 0; i != NumElts; ++i)
2844 MappedOps[i] = UDVal;
2845 MappedOps[NumElts ] = *(N->getOperand(0).Val->op_end()-2);
2846 MappedOps[NumElts+1] = *(N->getOperand(0).Val->op_end()-1);
2847 UDVal = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, MappedOps);
2849 return DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector,
2850 N->getOperand(0), UDVal, ShufMask,
2851 MappedOps[NumElts], MappedOps[NumElts+1]);
2857 /// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform
2858 /// a VAND to a vector_shuffle with the destination vector and a zero vector.
2859 /// e.g. VAND V, <0xffffffff, 0, 0xffffffff, 0>. ==>
2860 /// vector_shuffle V, Zero, <0, 4, 2, 4>
2861 SDOperand DAGCombiner::XformToShuffleWithZero(SDNode *N) {
2862 SDOperand LHS = N->getOperand(0);
2863 SDOperand RHS = N->getOperand(1);
2864 if (N->getOpcode() == ISD::VAND) {
2865 SDOperand DstVecSize = *(LHS.Val->op_end()-2);
2866 SDOperand DstVecEVT = *(LHS.Val->op_end()-1);
2867 if (RHS.getOpcode() == ISD::VBIT_CONVERT)
2868 RHS = RHS.getOperand(0);
2869 if (RHS.getOpcode() == ISD::VBUILD_VECTOR) {
2870 std::vector<SDOperand> IdxOps;
2871 unsigned NumOps = RHS.getNumOperands();
2872 unsigned NumElts = NumOps-2;
2873 MVT::ValueType EVT = cast<VTSDNode>(RHS.getOperand(NumOps-1))->getVT();
2874 for (unsigned i = 0; i != NumElts; ++i) {
2875 SDOperand Elt = RHS.getOperand(i);
2876 if (!isa<ConstantSDNode>(Elt))
2878 else if (cast<ConstantSDNode>(Elt)->isAllOnesValue())
2879 IdxOps.push_back(DAG.getConstant(i, EVT));
2880 else if (cast<ConstantSDNode>(Elt)->isNullValue())
2881 IdxOps.push_back(DAG.getConstant(NumElts, EVT));
2886 // Let's see if the target supports this vector_shuffle.
2887 if (!TLI.isVectorClearMaskLegal(IdxOps, EVT, DAG))
2890 // Return the new VVECTOR_SHUFFLE node.
2891 SDOperand NumEltsNode = DAG.getConstant(NumElts, MVT::i32);
2892 SDOperand EVTNode = DAG.getValueType(EVT);
2893 std::vector<SDOperand> Ops;
2894 LHS = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, LHS, NumEltsNode, EVTNode);
2896 AddToWorkList(LHS.Val);
2897 std::vector<SDOperand> ZeroOps(NumElts, DAG.getConstant(0, EVT));
2898 ZeroOps.push_back(NumEltsNode);
2899 ZeroOps.push_back(EVTNode);
2900 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, ZeroOps));
2901 IdxOps.push_back(NumEltsNode);
2902 IdxOps.push_back(EVTNode);
2903 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, IdxOps));
2904 Ops.push_back(NumEltsNode);
2905 Ops.push_back(EVTNode);
2906 SDOperand Result = DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector, Ops);
2907 if (NumEltsNode != DstVecSize || EVTNode != DstVecEVT) {
2908 Result = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, Result,
2909 DstVecSize, DstVecEVT);
2917 /// visitVBinOp - Visit a binary vector operation, like VADD. IntOp indicates
2918 /// the scalar operation of the vop if it is operating on an integer vector
2919 /// (e.g. ADD) and FPOp indicates the FP version (e.g. FADD).
2920 SDOperand DAGCombiner::visitVBinOp(SDNode *N, ISD::NodeType IntOp,
2921 ISD::NodeType FPOp) {
2922 MVT::ValueType EltType = cast<VTSDNode>(*(N->op_end()-1))->getVT();
2923 ISD::NodeType ScalarOp = MVT::isInteger(EltType) ? IntOp : FPOp;
2924 SDOperand LHS = N->getOperand(0);
2925 SDOperand RHS = N->getOperand(1);
2926 SDOperand Shuffle = XformToShuffleWithZero(N);
2927 if (Shuffle.Val) return Shuffle;
2929 // If the LHS and RHS are VBUILD_VECTOR nodes, see if we can constant fold
2931 if (LHS.getOpcode() == ISD::VBUILD_VECTOR &&
2932 RHS.getOpcode() == ISD::VBUILD_VECTOR) {
2933 std::vector<SDOperand> Ops;
2934 for (unsigned i = 0, e = LHS.getNumOperands()-2; i != e; ++i) {
2935 SDOperand LHSOp = LHS.getOperand(i);
2936 SDOperand RHSOp = RHS.getOperand(i);
2937 // If these two elements can't be folded, bail out.
2938 if ((LHSOp.getOpcode() != ISD::UNDEF &&
2939 LHSOp.getOpcode() != ISD::Constant &&
2940 LHSOp.getOpcode() != ISD::ConstantFP) ||
2941 (RHSOp.getOpcode() != ISD::UNDEF &&
2942 RHSOp.getOpcode() != ISD::Constant &&
2943 RHSOp.getOpcode() != ISD::ConstantFP))
2945 Ops.push_back(DAG.getNode(ScalarOp, EltType, LHSOp, RHSOp));
2946 AddToWorkList(Ops.back().Val);
2947 assert((Ops.back().getOpcode() == ISD::UNDEF ||
2948 Ops.back().getOpcode() == ISD::Constant ||
2949 Ops.back().getOpcode() == ISD::ConstantFP) &&
2950 "Scalar binop didn't fold!");
2953 if (Ops.size() == LHS.getNumOperands()-2) {
2954 Ops.push_back(*(LHS.Val->op_end()-2));
2955 Ops.push_back(*(LHS.Val->op_end()-1));
2956 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, Ops);
2963 SDOperand DAGCombiner::SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2){
2964 assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!");
2966 SDOperand SCC = SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), N1, N2,
2967 cast<CondCodeSDNode>(N0.getOperand(2))->get());
2968 // If we got a simplified select_cc node back from SimplifySelectCC, then
2969 // break it down into a new SETCC node, and a new SELECT node, and then return
2970 // the SELECT node, since we were called with a SELECT node.
2972 // Check to see if we got a select_cc back (to turn into setcc/select).
2973 // Otherwise, just return whatever node we got back, like fabs.
2974 if (SCC.getOpcode() == ISD::SELECT_CC) {
2975 SDOperand SETCC = DAG.getNode(ISD::SETCC, N0.getValueType(),
2976 SCC.getOperand(0), SCC.getOperand(1),
2978 AddToWorkList(SETCC.Val);
2979 return DAG.getNode(ISD::SELECT, SCC.getValueType(), SCC.getOperand(2),
2980 SCC.getOperand(3), SETCC);
2987 /// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS
2988 /// are the two values being selected between, see if we can simplify the
2991 bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDOperand LHS,
2994 // If this is a select from two identical things, try to pull the operation
2995 // through the select.
2996 if (LHS.getOpcode() == RHS.getOpcode() && LHS.hasOneUse() && RHS.hasOneUse()){
2998 std::cerr << "SELECT: ["; LHS.Val->dump();
2999 std::cerr << "] ["; RHS.Val->dump();
3003 // If this is a load and the token chain is identical, replace the select
3004 // of two loads with a load through a select of the address to load from.
3005 // This triggers in things like "select bool X, 10.0, 123.0" after the FP
3006 // constants have been dropped into the constant pool.
3007 if ((LHS.getOpcode() == ISD::LOAD ||
3008 LHS.getOpcode() == ISD::EXTLOAD ||
3009 LHS.getOpcode() == ISD::ZEXTLOAD ||
3010 LHS.getOpcode() == ISD::SEXTLOAD) &&
3011 // Token chains must be identical.
3012 LHS.getOperand(0) == RHS.getOperand(0) &&
3013 // If this is an EXTLOAD, the VT's must match.
3014 (LHS.getOpcode() == ISD::LOAD ||
3015 LHS.getOperand(3) == RHS.getOperand(3))) {
3016 // FIXME: this conflates two src values, discarding one. This is not
3017 // the right thing to do, but nothing uses srcvalues now. When they do,
3018 // turn SrcValue into a list of locations.
3020 if (TheSelect->getOpcode() == ISD::SELECT)
3021 Addr = DAG.getNode(ISD::SELECT, LHS.getOperand(1).getValueType(),
3022 TheSelect->getOperand(0), LHS.getOperand(1),
3025 Addr = DAG.getNode(ISD::SELECT_CC, LHS.getOperand(1).getValueType(),
3026 TheSelect->getOperand(0),
3027 TheSelect->getOperand(1),
3028 LHS.getOperand(1), RHS.getOperand(1),
3029 TheSelect->getOperand(4));
3032 if (LHS.getOpcode() == ISD::LOAD)
3033 Load = DAG.getLoad(TheSelect->getValueType(0), LHS.getOperand(0),
3034 Addr, LHS.getOperand(2));
3036 Load = DAG.getExtLoad(LHS.getOpcode(), TheSelect->getValueType(0),
3037 LHS.getOperand(0), Addr, LHS.getOperand(2),
3038 cast<VTSDNode>(LHS.getOperand(3))->getVT());
3039 // Users of the select now use the result of the load.
3040 CombineTo(TheSelect, Load);
3042 // Users of the old loads now use the new load's chain. We know the
3043 // old-load value is dead now.
3044 CombineTo(LHS.Val, Load.getValue(0), Load.getValue(1));
3045 CombineTo(RHS.Val, Load.getValue(0), Load.getValue(1));
3053 SDOperand DAGCombiner::SimplifySelectCC(SDOperand N0, SDOperand N1,
3054 SDOperand N2, SDOperand N3,
3057 MVT::ValueType VT = N2.getValueType();
3058 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
3059 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
3060 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.Val);
3061 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.Val);
3063 // Determine if the condition we're dealing with is constant
3064 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false);
3065 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val);
3067 // fold select_cc true, x, y -> x
3068 if (SCCC && SCCC->getValue())
3070 // fold select_cc false, x, y -> y
3071 if (SCCC && SCCC->getValue() == 0)
3074 // Check to see if we can simplify the select into an fabs node
3075 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) {
3076 // Allow either -0.0 or 0.0
3077 if (CFP->getValue() == 0.0) {
3078 // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs
3079 if ((CC == ISD::SETGE || CC == ISD::SETGT) &&
3080 N0 == N2 && N3.getOpcode() == ISD::FNEG &&
3081 N2 == N3.getOperand(0))
3082 return DAG.getNode(ISD::FABS, VT, N0);
3084 // select (setl[te] X, +/-0.0), fneg(X), X -> fabs
3085 if ((CC == ISD::SETLT || CC == ISD::SETLE) &&
3086 N0 == N3 && N2.getOpcode() == ISD::FNEG &&
3087 N2.getOperand(0) == N3)
3088 return DAG.getNode(ISD::FABS, VT, N3);
3092 // Check to see if we can perform the "gzip trick", transforming
3093 // select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A
3094 if (N1C && N1C->isNullValue() && N3C && N3C->isNullValue() &&
3095 MVT::isInteger(N0.getValueType()) &&
3096 MVT::isInteger(N2.getValueType()) && CC == ISD::SETLT) {
3097 MVT::ValueType XType = N0.getValueType();
3098 MVT::ValueType AType = N2.getValueType();
3099 if (XType >= AType) {
3100 // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a
3101 // single-bit constant.
3102 if (N2C && ((N2C->getValue() & (N2C->getValue()-1)) == 0)) {
3103 unsigned ShCtV = Log2_64(N2C->getValue());
3104 ShCtV = MVT::getSizeInBits(XType)-ShCtV-1;
3105 SDOperand ShCt = DAG.getConstant(ShCtV, TLI.getShiftAmountTy());
3106 SDOperand Shift = DAG.getNode(ISD::SRL, XType, N0, ShCt);
3107 AddToWorkList(Shift.Val);
3108 if (XType > AType) {
3109 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift);
3110 AddToWorkList(Shift.Val);
3112 return DAG.getNode(ISD::AND, AType, Shift, N2);
3114 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0,
3115 DAG.getConstant(MVT::getSizeInBits(XType)-1,
3116 TLI.getShiftAmountTy()));
3117 AddToWorkList(Shift.Val);
3118 if (XType > AType) {
3119 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift);
3120 AddToWorkList(Shift.Val);
3122 return DAG.getNode(ISD::AND, AType, Shift, N2);
3126 // fold select C, 16, 0 -> shl C, 4
3127 if (N2C && N3C && N3C->isNullValue() && isPowerOf2_64(N2C->getValue()) &&
3128 TLI.getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult) {
3129 // Get a SetCC of the condition
3130 // FIXME: Should probably make sure that setcc is legal if we ever have a
3131 // target where it isn't.
3132 SDOperand Temp, SCC;
3133 // cast from setcc result type to select result type
3134 if (AfterLegalize) {
3135 SCC = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC);
3136 Temp = DAG.getZeroExtendInReg(SCC, N2.getValueType());
3138 SCC = DAG.getSetCC(MVT::i1, N0, N1, CC);
3139 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getValueType(), SCC);
3141 AddToWorkList(SCC.Val);
3142 AddToWorkList(Temp.Val);
3143 // shl setcc result by log2 n2c
3144 return DAG.getNode(ISD::SHL, N2.getValueType(), Temp,
3145 DAG.getConstant(Log2_64(N2C->getValue()),
3146 TLI.getShiftAmountTy()));
3149 // Check to see if this is the equivalent of setcc
3150 // FIXME: Turn all of these into setcc if setcc if setcc is legal
3151 // otherwise, go ahead with the folds.
3152 if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getValue() == 1ULL)) {
3153 MVT::ValueType XType = N0.getValueType();
3154 if (TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultTy())) {
3155 SDOperand Res = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC);
3156 if (Res.getValueType() != VT)
3157 Res = DAG.getNode(ISD::ZERO_EXTEND, VT, Res);
3161 // seteq X, 0 -> srl (ctlz X, log2(size(X)))
3162 if (N1C && N1C->isNullValue() && CC == ISD::SETEQ &&
3163 TLI.isOperationLegal(ISD::CTLZ, XType)) {
3164 SDOperand Ctlz = DAG.getNode(ISD::CTLZ, XType, N0);
3165 return DAG.getNode(ISD::SRL, XType, Ctlz,
3166 DAG.getConstant(Log2_32(MVT::getSizeInBits(XType)),
3167 TLI.getShiftAmountTy()));
3169 // setgt X, 0 -> srl (and (-X, ~X), size(X)-1)
3170 if (N1C && N1C->isNullValue() && CC == ISD::SETGT) {
3171 SDOperand NegN0 = DAG.getNode(ISD::SUB, XType, DAG.getConstant(0, XType),
3173 SDOperand NotN0 = DAG.getNode(ISD::XOR, XType, N0,
3174 DAG.getConstant(~0ULL, XType));
3175 return DAG.getNode(ISD::SRL, XType,
3176 DAG.getNode(ISD::AND, XType, NegN0, NotN0),
3177 DAG.getConstant(MVT::getSizeInBits(XType)-1,
3178 TLI.getShiftAmountTy()));
3180 // setgt X, -1 -> xor (srl (X, size(X)-1), 1)
3181 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) {
3182 SDOperand Sign = DAG.getNode(ISD::SRL, XType, N0,
3183 DAG.getConstant(MVT::getSizeInBits(XType)-1,
3184 TLI.getShiftAmountTy()));
3185 return DAG.getNode(ISD::XOR, XType, Sign, DAG.getConstant(1, XType));
3189 // Check to see if this is an integer abs. select_cc setl[te] X, 0, -X, X ->
3190 // Y = sra (X, size(X)-1); xor (add (X, Y), Y)
3191 if (N1C && N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE) &&
3192 N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1)) {
3193 if (ConstantSDNode *SubC = dyn_cast<ConstantSDNode>(N2.getOperand(0))) {
3194 MVT::ValueType XType = N0.getValueType();
3195 if (SubC->isNullValue() && MVT::isInteger(XType)) {
3196 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0,
3197 DAG.getConstant(MVT::getSizeInBits(XType)-1,
3198 TLI.getShiftAmountTy()));
3199 SDOperand Add = DAG.getNode(ISD::ADD, XType, N0, Shift);
3200 AddToWorkList(Shift.Val);
3201 AddToWorkList(Add.Val);
3202 return DAG.getNode(ISD::XOR, XType, Add, Shift);
3210 SDOperand DAGCombiner::SimplifySetCC(MVT::ValueType VT, SDOperand N0,
3211 SDOperand N1, ISD::CondCode Cond,
3212 bool foldBooleans) {
3213 // These setcc operations always fold.
3217 case ISD::SETFALSE2: return DAG.getConstant(0, VT);
3219 case ISD::SETTRUE2: return DAG.getConstant(1, VT);
3222 if (ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val)) {
3223 uint64_t C1 = N1C->getValue();
3224 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val)) {
3225 uint64_t C0 = N0C->getValue();
3227 // Sign extend the operands if required
3228 if (ISD::isSignedIntSetCC(Cond)) {
3229 C0 = N0C->getSignExtended();
3230 C1 = N1C->getSignExtended();
3234 default: assert(0 && "Unknown integer setcc!");
3235 case ISD::SETEQ: return DAG.getConstant(C0 == C1, VT);
3236 case ISD::SETNE: return DAG.getConstant(C0 != C1, VT);
3237 case ISD::SETULT: return DAG.getConstant(C0 < C1, VT);
3238 case ISD::SETUGT: return DAG.getConstant(C0 > C1, VT);
3239 case ISD::SETULE: return DAG.getConstant(C0 <= C1, VT);
3240 case ISD::SETUGE: return DAG.getConstant(C0 >= C1, VT);
3241 case ISD::SETLT: return DAG.getConstant((int64_t)C0 < (int64_t)C1, VT);
3242 case ISD::SETGT: return DAG.getConstant((int64_t)C0 > (int64_t)C1, VT);
3243 case ISD::SETLE: return DAG.getConstant((int64_t)C0 <= (int64_t)C1, VT);
3244 case ISD::SETGE: return DAG.getConstant((int64_t)C0 >= (int64_t)C1, VT);
3247 // If the LHS is a ZERO_EXTEND, perform the comparison on the input.
3248 if (N0.getOpcode() == ISD::ZERO_EXTEND) {
3249 unsigned InSize = MVT::getSizeInBits(N0.getOperand(0).getValueType());
3251 // If the comparison constant has bits in the upper part, the
3252 // zero-extended value could never match.
3253 if (C1 & (~0ULL << InSize)) {
3254 unsigned VSize = MVT::getSizeInBits(N0.getValueType());
3258 case ISD::SETEQ: return DAG.getConstant(0, VT);
3261 case ISD::SETNE: return DAG.getConstant(1, VT);
3264 // True if the sign bit of C1 is set.
3265 return DAG.getConstant((C1 & (1ULL << VSize)) != 0, VT);
3268 // True if the sign bit of C1 isn't set.
3269 return DAG.getConstant((C1 & (1ULL << VSize)) == 0, VT);
3275 // Otherwise, we can perform the comparison with the low bits.
3283 return DAG.getSetCC(VT, N0.getOperand(0),
3284 DAG.getConstant(C1, N0.getOperand(0).getValueType()),
3287 break; // todo, be more careful with signed comparisons
3289 } else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
3290 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
3291 MVT::ValueType ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT();
3292 unsigned ExtSrcTyBits = MVT::getSizeInBits(ExtSrcTy);
3293 MVT::ValueType ExtDstTy = N0.getValueType();
3294 unsigned ExtDstTyBits = MVT::getSizeInBits(ExtDstTy);
3296 // If the extended part has any inconsistent bits, it cannot ever
3297 // compare equal. In other words, they have to be all ones or all
3300 (~0ULL >> (64-ExtSrcTyBits)) & (~0ULL << (ExtDstTyBits-1));
3301 if ((C1 & ExtBits) != 0 && (C1 & ExtBits) != ExtBits)
3302 return DAG.getConstant(Cond == ISD::SETNE, VT);
3305 MVT::ValueType Op0Ty = N0.getOperand(0).getValueType();
3306 if (Op0Ty == ExtSrcTy) {
3307 ZextOp = N0.getOperand(0);
3309 int64_t Imm = ~0ULL >> (64-ExtSrcTyBits);
3310 ZextOp = DAG.getNode(ISD::AND, Op0Ty, N0.getOperand(0),
3311 DAG.getConstant(Imm, Op0Ty));
3313 AddToWorkList(ZextOp.Val);
3314 // Otherwise, make this a use of a zext.
3315 return DAG.getSetCC(VT, ZextOp,
3316 DAG.getConstant(C1 & (~0ULL>>(64-ExtSrcTyBits)),
3319 } else if ((N1C->getValue() == 0 || N1C->getValue() == 1) &&
3320 (Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
3321 (N0.getOpcode() == ISD::XOR ||
3322 (N0.getOpcode() == ISD::AND &&
3323 N0.getOperand(0).getOpcode() == ISD::XOR &&
3324 N0.getOperand(1) == N0.getOperand(0).getOperand(1))) &&
3325 isa<ConstantSDNode>(N0.getOperand(1)) &&
3326 cast<ConstantSDNode>(N0.getOperand(1))->getValue() == 1) {
3327 // If this is (X^1) == 0/1, swap the RHS and eliminate the xor. We can
3328 // only do this if the top bits are known zero.
3329 if (TLI.MaskedValueIsZero(N1,
3330 MVT::getIntVTBitMask(N0.getValueType())-1)) {
3331 // Okay, get the un-inverted input value.
3333 if (N0.getOpcode() == ISD::XOR)
3334 Val = N0.getOperand(0);
3336 assert(N0.getOpcode() == ISD::AND &&
3337 N0.getOperand(0).getOpcode() == ISD::XOR);
3338 // ((X^1)&1)^1 -> X & 1
3339 Val = DAG.getNode(ISD::AND, N0.getValueType(),
3340 N0.getOperand(0).getOperand(0), N0.getOperand(1));
3342 return DAG.getSetCC(VT, Val, N1,
3343 Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
3347 uint64_t MinVal, MaxVal;
3348 unsigned OperandBitSize = MVT::getSizeInBits(N1C->getValueType(0));
3349 if (ISD::isSignedIntSetCC(Cond)) {
3350 MinVal = 1ULL << (OperandBitSize-1);
3351 if (OperandBitSize != 1) // Avoid X >> 64, which is undefined.
3352 MaxVal = ~0ULL >> (65-OperandBitSize);
3357 MaxVal = ~0ULL >> (64-OperandBitSize);
3360 // Canonicalize GE/LE comparisons to use GT/LT comparisons.
3361 if (Cond == ISD::SETGE || Cond == ISD::SETUGE) {
3362 if (C1 == MinVal) return DAG.getConstant(1, VT); // X >= MIN --> true
3363 --C1; // X >= C0 --> X > (C0-1)
3364 return DAG.getSetCC(VT, N0, DAG.getConstant(C1, N1.getValueType()),
3365 (Cond == ISD::SETGE) ? ISD::SETGT : ISD::SETUGT);
3368 if (Cond == ISD::SETLE || Cond == ISD::SETULE) {
3369 if (C1 == MaxVal) return DAG.getConstant(1, VT); // X <= MAX --> true
3370 ++C1; // X <= C0 --> X < (C0+1)
3371 return DAG.getSetCC(VT, N0, DAG.getConstant(C1, N1.getValueType()),
3372 (Cond == ISD::SETLE) ? ISD::SETLT : ISD::SETULT);
3375 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal)
3376 return DAG.getConstant(0, VT); // X < MIN --> false
3378 // Canonicalize setgt X, Min --> setne X, Min
3379 if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MinVal)
3380 return DAG.getSetCC(VT, N0, N1, ISD::SETNE);
3381 // Canonicalize setlt X, Max --> setne X, Max
3382 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MaxVal)
3383 return DAG.getSetCC(VT, N0, N1, ISD::SETNE);
3385 // If we have setult X, 1, turn it into seteq X, 0
3386 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal+1)
3387 return DAG.getSetCC(VT, N0, DAG.getConstant(MinVal, N0.getValueType()),
3389 // If we have setugt X, Max-1, turn it into seteq X, Max
3390 else if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal-1)
3391 return DAG.getSetCC(VT, N0, DAG.getConstant(MaxVal, N0.getValueType()),
3394 // If we have "setcc X, C0", check to see if we can shrink the immediate
3397 // SETUGT X, SINTMAX -> SETLT X, 0
3398 if (Cond == ISD::SETUGT && OperandBitSize != 1 &&
3399 C1 == (~0ULL >> (65-OperandBitSize)))
3400 return DAG.getSetCC(VT, N0, DAG.getConstant(0, N1.getValueType()),
3403 // FIXME: Implement the rest of these.
3405 // Fold bit comparisons when we can.
3406 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
3407 VT == N0.getValueType() && N0.getOpcode() == ISD::AND)
3408 if (ConstantSDNode *AndRHS =
3409 dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
3410 if (Cond == ISD::SETNE && C1 == 0) {// (X & 8) != 0 --> (X & 8) >> 3
3411 // Perform the xform if the AND RHS is a single bit.
3412 if ((AndRHS->getValue() & (AndRHS->getValue()-1)) == 0) {
3413 return DAG.getNode(ISD::SRL, VT, N0,
3414 DAG.getConstant(Log2_64(AndRHS->getValue()),
3415 TLI.getShiftAmountTy()));
3417 } else if (Cond == ISD::SETEQ && C1 == AndRHS->getValue()) {
3418 // (X & 8) == 8 --> (X & 8) >> 3
3419 // Perform the xform if C1 is a single bit.
3420 if ((C1 & (C1-1)) == 0) {
3421 return DAG.getNode(ISD::SRL, VT, N0,
3422 DAG.getConstant(Log2_64(C1),TLI.getShiftAmountTy()));
3427 } else if (isa<ConstantSDNode>(N0.Val)) {
3428 // Ensure that the constant occurs on the RHS.
3429 return DAG.getSetCC(VT, N1, N0, ISD::getSetCCSwappedOperands(Cond));
3432 if (ConstantFPSDNode *N0C = dyn_cast<ConstantFPSDNode>(N0.Val))
3433 if (ConstantFPSDNode *N1C = dyn_cast<ConstantFPSDNode>(N1.Val)) {
3434 double C0 = N0C->getValue(), C1 = N1C->getValue();
3437 default: break; // FIXME: Implement the rest of these!
3438 case ISD::SETEQ: return DAG.getConstant(C0 == C1, VT);
3439 case ISD::SETNE: return DAG.getConstant(C0 != C1, VT);
3440 case ISD::SETLT: return DAG.getConstant(C0 < C1, VT);
3441 case ISD::SETGT: return DAG.getConstant(C0 > C1, VT);
3442 case ISD::SETLE: return DAG.getConstant(C0 <= C1, VT);
3443 case ISD::SETGE: return DAG.getConstant(C0 >= C1, VT);
3446 // Ensure that the constant occurs on the RHS.
3447 return DAG.getSetCC(VT, N1, N0, ISD::getSetCCSwappedOperands(Cond));
3451 // We can always fold X == Y for integer setcc's.
3452 if (MVT::isInteger(N0.getValueType()))
3453 return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
3454 unsigned UOF = ISD::getUnorderedFlavor(Cond);
3455 if (UOF == 2) // FP operators that are undefined on NaNs.
3456 return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
3457 if (UOF == unsigned(ISD::isTrueWhenEqual(Cond)))
3458 return DAG.getConstant(UOF, VT);
3459 // Otherwise, we can't fold it. However, we can simplify it to SETUO/SETO
3460 // if it is not already.
3461 ISD::CondCode NewCond = UOF == 0 ? ISD::SETO : ISD::SETUO;
3462 if (NewCond != Cond)
3463 return DAG.getSetCC(VT, N0, N1, NewCond);
3466 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
3467 MVT::isInteger(N0.getValueType())) {
3468 if (N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::SUB ||
3469 N0.getOpcode() == ISD::XOR) {
3470 // Simplify (X+Y) == (X+Z) --> Y == Z
3471 if (N0.getOpcode() == N1.getOpcode()) {
3472 if (N0.getOperand(0) == N1.getOperand(0))
3473 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(1), Cond);
3474 if (N0.getOperand(1) == N1.getOperand(1))
3475 return DAG.getSetCC(VT, N0.getOperand(0), N1.getOperand(0), Cond);
3476 if (isCommutativeBinOp(N0.getOpcode())) {
3477 // If X op Y == Y op X, try other combinations.
3478 if (N0.getOperand(0) == N1.getOperand(1))
3479 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(0), Cond);
3480 if (N0.getOperand(1) == N1.getOperand(0))
3481 return DAG.getSetCC(VT, N0.getOperand(0), N1.getOperand(1), Cond);
3485 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(N1)) {
3486 if (ConstantSDNode *LHSR = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
3487 // Turn (X+C1) == C2 --> X == C2-C1
3488 if (N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse()) {
3489 return DAG.getSetCC(VT, N0.getOperand(0),
3490 DAG.getConstant(RHSC->getValue()-LHSR->getValue(),
3491 N0.getValueType()), Cond);
3494 // Turn (X^C1) == C2 into X == C1^C2 iff X&~C1 = 0.
3495 if (N0.getOpcode() == ISD::XOR)
3496 // If we know that all of the inverted bits are zero, don't bother
3497 // performing the inversion.
3498 if (TLI.MaskedValueIsZero(N0.getOperand(0), ~LHSR->getValue()))
3499 return DAG.getSetCC(VT, N0.getOperand(0),
3500 DAG.getConstant(LHSR->getValue()^RHSC->getValue(),
3501 N0.getValueType()), Cond);
3504 // Turn (C1-X) == C2 --> X == C1-C2
3505 if (ConstantSDNode *SUBC = dyn_cast<ConstantSDNode>(N0.getOperand(0))) {
3506 if (N0.getOpcode() == ISD::SUB && N0.Val->hasOneUse()) {
3507 return DAG.getSetCC(VT, N0.getOperand(1),
3508 DAG.getConstant(SUBC->getValue()-RHSC->getValue(),
3509 N0.getValueType()), Cond);
3514 // Simplify (X+Z) == X --> Z == 0
3515 if (N0.getOperand(0) == N1)
3516 return DAG.getSetCC(VT, N0.getOperand(1),
3517 DAG.getConstant(0, N0.getValueType()), Cond);
3518 if (N0.getOperand(1) == N1) {
3519 if (isCommutativeBinOp(N0.getOpcode()))
3520 return DAG.getSetCC(VT, N0.getOperand(0),
3521 DAG.getConstant(0, N0.getValueType()), Cond);
3523 assert(N0.getOpcode() == ISD::SUB && "Unexpected operation!");
3524 // (Z-X) == X --> Z == X<<1
3525 SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(),
3527 DAG.getConstant(1,TLI.getShiftAmountTy()));
3528 AddToWorkList(SH.Val);
3529 return DAG.getSetCC(VT, N0.getOperand(0), SH, Cond);
3534 if (N1.getOpcode() == ISD::ADD || N1.getOpcode() == ISD::SUB ||
3535 N1.getOpcode() == ISD::XOR) {
3536 // Simplify X == (X+Z) --> Z == 0
3537 if (N1.getOperand(0) == N0) {
3538 return DAG.getSetCC(VT, N1.getOperand(1),
3539 DAG.getConstant(0, N1.getValueType()), Cond);
3540 } else if (N1.getOperand(1) == N0) {
3541 if (isCommutativeBinOp(N1.getOpcode())) {
3542 return DAG.getSetCC(VT, N1.getOperand(0),
3543 DAG.getConstant(0, N1.getValueType()), Cond);
3545 assert(N1.getOpcode() == ISD::SUB && "Unexpected operation!");
3546 // X == (Z-X) --> X<<1 == Z
3547 SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(), N0,
3548 DAG.getConstant(1,TLI.getShiftAmountTy()));
3549 AddToWorkList(SH.Val);
3550 return DAG.getSetCC(VT, SH, N1.getOperand(0), Cond);
3556 // Fold away ALL boolean setcc's.
3558 if (N0.getValueType() == MVT::i1 && foldBooleans) {
3560 default: assert(0 && "Unknown integer setcc!");
3561 case ISD::SETEQ: // X == Y -> (X^Y)^1
3562 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, N1);
3563 N0 = DAG.getNode(ISD::XOR, MVT::i1, Temp, DAG.getConstant(1, MVT::i1));
3564 AddToWorkList(Temp.Val);
3566 case ISD::SETNE: // X != Y --> (X^Y)
3567 N0 = DAG.getNode(ISD::XOR, MVT::i1, N0, N1);
3569 case ISD::SETGT: // X >s Y --> X == 0 & Y == 1 --> X^1 & Y
3570 case ISD::SETULT: // X <u Y --> X == 0 & Y == 1 --> X^1 & Y
3571 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1));
3572 N0 = DAG.getNode(ISD::AND, MVT::i1, N1, Temp);
3573 AddToWorkList(Temp.Val);
3575 case ISD::SETLT: // X <s Y --> X == 1 & Y == 0 --> Y^1 & X
3576 case ISD::SETUGT: // X >u Y --> X == 1 & Y == 0 --> Y^1 & X
3577 Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1));
3578 N0 = DAG.getNode(ISD::AND, MVT::i1, N0, Temp);
3579 AddToWorkList(Temp.Val);
3581 case ISD::SETULE: // X <=u Y --> X == 0 | Y == 1 --> X^1 | Y
3582 case ISD::SETGE: // X >=s Y --> X == 0 | Y == 1 --> X^1 | Y
3583 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1));
3584 N0 = DAG.getNode(ISD::OR, MVT::i1, N1, Temp);
3585 AddToWorkList(Temp.Val);
3587 case ISD::SETUGE: // X >=u Y --> X == 1 | Y == 0 --> Y^1 | X
3588 case ISD::SETLE: // X <=s Y --> X == 1 | Y == 0 --> Y^1 | X
3589 Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1));
3590 N0 = DAG.getNode(ISD::OR, MVT::i1, N0, Temp);
3593 if (VT != MVT::i1) {
3594 AddToWorkList(N0.Val);
3595 // FIXME: If running after legalize, we probably can't do this.
3596 N0 = DAG.getNode(ISD::ZERO_EXTEND, VT, N0);
3601 // Could not fold it.
3605 /// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant,
3606 /// return a DAG expression to select that will generate the same value by
3607 /// multiplying by a magic number. See:
3608 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
3609 SDOperand DAGCombiner::BuildSDIV(SDNode *N) {
3610 MVT::ValueType VT = N->getValueType(0);
3612 // Check to see if we can do this.
3613 if (!TLI.isTypeLegal(VT) || (VT != MVT::i32 && VT != MVT::i64))
3614 return SDOperand(); // BuildSDIV only operates on i32 or i64
3615 if (!TLI.isOperationLegal(ISD::MULHS, VT))
3616 return SDOperand(); // Make sure the target supports MULHS.
3618 int64_t d = cast<ConstantSDNode>(N->getOperand(1))->getSignExtended();
3619 ms magics = (VT == MVT::i32) ? magic32(d) : magic64(d);
3621 // Multiply the numerator (operand 0) by the magic value
3622 SDOperand Q = DAG.getNode(ISD::MULHS, VT, N->getOperand(0),
3623 DAG.getConstant(magics.m, VT));
3624 // If d > 0 and m < 0, add the numerator
3625 if (d > 0 && magics.m < 0) {
3626 Q = DAG.getNode(ISD::ADD, VT, Q, N->getOperand(0));
3627 AddToWorkList(Q.Val);
3629 // If d < 0 and m > 0, subtract the numerator.
3630 if (d < 0 && magics.m > 0) {
3631 Q = DAG.getNode(ISD::SUB, VT, Q, N->getOperand(0));
3632 AddToWorkList(Q.Val);
3634 // Shift right algebraic if shift value is nonzero
3636 Q = DAG.getNode(ISD::SRA, VT, Q,
3637 DAG.getConstant(magics.s, TLI.getShiftAmountTy()));
3638 AddToWorkList(Q.Val);
3640 // Extract the sign bit and add it to the quotient
3642 DAG.getNode(ISD::SRL, VT, Q, DAG.getConstant(MVT::getSizeInBits(VT)-1,
3643 TLI.getShiftAmountTy()));
3644 AddToWorkList(T.Val);
3645 return DAG.getNode(ISD::ADD, VT, Q, T);
3648 /// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant,
3649 /// return a DAG expression to select that will generate the same value by
3650 /// multiplying by a magic number. See:
3651 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
3652 SDOperand DAGCombiner::BuildUDIV(SDNode *N) {
3653 MVT::ValueType VT = N->getValueType(0);
3655 // Check to see if we can do this.
3656 if (!TLI.isTypeLegal(VT) || (VT != MVT::i32 && VT != MVT::i64))
3657 return SDOperand(); // BuildUDIV only operates on i32 or i64
3658 if (!TLI.isOperationLegal(ISD::MULHU, VT))
3659 return SDOperand(); // Make sure the target supports MULHU.
3661 uint64_t d = cast<ConstantSDNode>(N->getOperand(1))->getValue();
3662 mu magics = (VT == MVT::i32) ? magicu32(d) : magicu64(d);
3664 // Multiply the numerator (operand 0) by the magic value
3665 SDOperand Q = DAG.getNode(ISD::MULHU, VT, N->getOperand(0),
3666 DAG.getConstant(magics.m, VT));
3667 AddToWorkList(Q.Val);
3669 if (magics.a == 0) {
3670 return DAG.getNode(ISD::SRL, VT, Q,
3671 DAG.getConstant(magics.s, TLI.getShiftAmountTy()));
3673 SDOperand NPQ = DAG.getNode(ISD::SUB, VT, N->getOperand(0), Q);
3674 AddToWorkList(NPQ.Val);
3675 NPQ = DAG.getNode(ISD::SRL, VT, NPQ,
3676 DAG.getConstant(1, TLI.getShiftAmountTy()));
3677 AddToWorkList(NPQ.Val);
3678 NPQ = DAG.getNode(ISD::ADD, VT, NPQ, Q);
3679 AddToWorkList(NPQ.Val);
3680 return DAG.getNode(ISD::SRL, VT, NPQ,
3681 DAG.getConstant(magics.s-1, TLI.getShiftAmountTy()));
3685 // SelectionDAG::Combine - This is the entry point for the file.
3687 void SelectionDAG::Combine(bool RunningAfterLegalize) {
3688 /// run - This is the main entry point to this class.
3690 DAGCombiner(*this).Run(RunningAfterLegalize);