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: Should add a corresponding version of fold AND with
20 // ZERO_EXTEND/SIGN_EXTEND by converting them to an ANY_EXTEND node which
23 // FIXME: select C, pow2, pow2 -> something smart
24 // FIXME: trunc(select X, Y, Z) -> select X, trunc(Y), trunc(Z)
25 // FIXME: (select C, load A, load B) -> load (select C, A, B)
26 // FIXME: Dead stores -> nuke
27 // FIXME: shr X, (and Y,31) -> shr X, Y
28 // FIXME: TRUNC (LOAD) -> EXT_LOAD/LOAD(smaller)
29 // FIXME: mul (x, const) -> shifts + adds
30 // FIXME: undef values
31 // FIXME: make truncate see through SIGN_EXTEND and AND
32 // FIXME: (sra (sra x, c1), c2) -> (sra x, c1+c2)
33 // FIXME: verify that getNode can't return extends with an operand whose type
34 // is >= to that of the extend.
35 // FIXME: divide by zero is currently left unfolded. do we want to turn this
37 // FIXME: select ne (select cc, 1, 0), 0, true, false -> select cc, true, false
38 // FIXME: reassociate (X+C)+Y into (X+Y)+C if the inner expression has one use
40 //===----------------------------------------------------------------------===//
42 #define DEBUG_TYPE "dagcombine"
43 #include "llvm/ADT/Statistic.h"
44 #include "llvm/CodeGen/SelectionDAG.h"
45 #include "llvm/Support/Debug.h"
46 #include "llvm/Support/MathExtras.h"
47 #include "llvm/Target/TargetLowering.h"
53 Statistic<> NodesCombined ("dagcombiner", "Number of dag nodes combined");
60 // Worklist of all of the nodes that need to be simplified.
61 std::vector<SDNode*> WorkList;
63 /// AddUsersToWorkList - When an instruction is simplified, add all users of
64 /// the instruction to the work lists because they might get more simplified
67 void AddUsersToWorkList(SDNode *N) {
68 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
70 WorkList.push_back(*UI);
73 /// removeFromWorkList - remove all instances of N from the worklist.
74 void removeFromWorkList(SDNode *N) {
75 WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N),
79 SDOperand CombineTo(SDNode *N, const std::vector<SDOperand> &To) {
81 DEBUG(std::cerr << "\nReplacing "; N->dump();
82 std::cerr << "\nWith: "; To[0].Val->dump();
83 std::cerr << " and " << To.size()-1 << " other values\n");
84 std::vector<SDNode*> NowDead;
85 DAG.ReplaceAllUsesWith(N, To, &NowDead);
87 // Push the new nodes and any users onto the worklist
88 for (unsigned i = 0, e = To.size(); i != e; ++i) {
89 WorkList.push_back(To[i].Val);
90 AddUsersToWorkList(To[i].Val);
93 // Nodes can end up on the worklist more than once. Make sure we do
94 // not process a node that has been replaced.
95 removeFromWorkList(N);
96 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
97 removeFromWorkList(NowDead[i]);
99 // Finally, since the node is now dead, remove it from the graph.
101 return SDOperand(N, 0);
104 SDOperand CombineTo(SDNode *N, SDOperand Res) {
105 std::vector<SDOperand> To;
107 return CombineTo(N, To);
110 SDOperand CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1) {
111 std::vector<SDOperand> To;
114 return CombineTo(N, To);
117 /// visit - call the node-specific routine that knows how to fold each
118 /// particular type of node.
119 SDOperand visit(SDNode *N);
121 // Visitation implementation - Implement dag node combining for different
122 // node types. The semantics are as follows:
124 // SDOperand.Val == 0 - No change was made
125 // SDOperand.Val == N - N was replaced, is dead, and is already handled.
126 // otherwise - N should be replaced by the returned Operand.
128 SDOperand visitTokenFactor(SDNode *N);
129 SDOperand visitADD(SDNode *N);
130 SDOperand visitSUB(SDNode *N);
131 SDOperand visitMUL(SDNode *N);
132 SDOperand visitSDIV(SDNode *N);
133 SDOperand visitUDIV(SDNode *N);
134 SDOperand visitSREM(SDNode *N);
135 SDOperand visitUREM(SDNode *N);
136 SDOperand visitMULHU(SDNode *N);
137 SDOperand visitMULHS(SDNode *N);
138 SDOperand visitAND(SDNode *N);
139 SDOperand visitOR(SDNode *N);
140 SDOperand visitXOR(SDNode *N);
141 SDOperand visitSHL(SDNode *N);
142 SDOperand visitSRA(SDNode *N);
143 SDOperand visitSRL(SDNode *N);
144 SDOperand visitCTLZ(SDNode *N);
145 SDOperand visitCTTZ(SDNode *N);
146 SDOperand visitCTPOP(SDNode *N);
147 SDOperand visitSELECT(SDNode *N);
148 SDOperand visitSELECT_CC(SDNode *N);
149 SDOperand visitSETCC(SDNode *N);
150 SDOperand visitSIGN_EXTEND(SDNode *N);
151 SDOperand visitZERO_EXTEND(SDNode *N);
152 SDOperand visitSIGN_EXTEND_INREG(SDNode *N);
153 SDOperand visitTRUNCATE(SDNode *N);
155 SDOperand visitFADD(SDNode *N);
156 SDOperand visitFSUB(SDNode *N);
157 SDOperand visitFMUL(SDNode *N);
158 SDOperand visitFDIV(SDNode *N);
159 SDOperand visitFREM(SDNode *N);
160 SDOperand visitSINT_TO_FP(SDNode *N);
161 SDOperand visitUINT_TO_FP(SDNode *N);
162 SDOperand visitFP_TO_SINT(SDNode *N);
163 SDOperand visitFP_TO_UINT(SDNode *N);
164 SDOperand visitFP_ROUND(SDNode *N);
165 SDOperand visitFP_ROUND_INREG(SDNode *N);
166 SDOperand visitFP_EXTEND(SDNode *N);
167 SDOperand visitFNEG(SDNode *N);
168 SDOperand visitFABS(SDNode *N);
169 SDOperand visitBRCOND(SDNode *N);
170 SDOperand visitBRCONDTWOWAY(SDNode *N);
171 SDOperand visitBR_CC(SDNode *N);
172 SDOperand visitBRTWOWAY_CC(SDNode *N);
174 SDOperand visitLOAD(SDNode *N);
175 SDOperand visitSTORE(SDNode *N);
177 SDOperand SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2);
178 SDOperand SimplifySelectCC(SDOperand N0, SDOperand N1, SDOperand N2,
179 SDOperand N3, ISD::CondCode CC);
180 SDOperand SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1,
181 ISD::CondCode Cond, bool foldBooleans = true);
183 DAGCombiner(SelectionDAG &D)
184 : DAG(D), TLI(D.getTargetLoweringInfo()), AfterLegalize(false) {}
186 /// Run - runs the dag combiner on all nodes in the work list
187 void Run(bool RunningAfterLegalize);
191 /// MaskedValueIsZero - Return true if 'Op & Mask' is known to be zero. We use
192 /// this predicate to simplify operations downstream. Op and Mask are known to
193 /// be the same type.
194 static bool MaskedValueIsZero(const SDOperand &Op, uint64_t Mask,
195 const TargetLowering &TLI) {
197 if (Mask == 0) return true;
199 // If we know the result of a setcc has the top bits zero, use this info.
200 switch (Op.getOpcode()) {
202 return (cast<ConstantSDNode>(Op)->getValue() & Mask) == 0;
204 return ((Mask & 1) == 0) &&
205 TLI.getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult;
207 SrcBits = MVT::getSizeInBits(cast<VTSDNode>(Op.getOperand(3))->getVT());
208 return (Mask & ((1ULL << SrcBits)-1)) == 0; // Returning only the zext bits.
209 case ISD::ZERO_EXTEND:
210 SrcBits = MVT::getSizeInBits(Op.getOperand(0).getValueType());
211 return MaskedValueIsZero(Op.getOperand(0),Mask & ((1ULL << SrcBits)-1),TLI);
212 case ISD::AssertZext:
213 SrcBits = MVT::getSizeInBits(cast<VTSDNode>(Op.getOperand(1))->getVT());
214 return (Mask & ((1ULL << SrcBits)-1)) == 0; // Returning only the zext bits.
216 // If either of the operands has zero bits, the result will too.
217 if (MaskedValueIsZero(Op.getOperand(1), Mask, TLI) ||
218 MaskedValueIsZero(Op.getOperand(0), Mask, TLI))
220 // (X & C1) & C2 == 0 iff C1 & C2 == 0.
221 if (ConstantSDNode *AndRHS = dyn_cast<ConstantSDNode>(Op.getOperand(1)))
222 return MaskedValueIsZero(Op.getOperand(0),AndRHS->getValue() & Mask, TLI);
226 return MaskedValueIsZero(Op.getOperand(0), Mask, TLI) &&
227 MaskedValueIsZero(Op.getOperand(1), Mask, TLI);
229 return MaskedValueIsZero(Op.getOperand(1), Mask, TLI) &&
230 MaskedValueIsZero(Op.getOperand(2), Mask, TLI);
232 return MaskedValueIsZero(Op.getOperand(2), Mask, TLI) &&
233 MaskedValueIsZero(Op.getOperand(3), Mask, TLI);
235 // (ushr X, C1) & C2 == 0 iff X & (C2 << C1) == 0
236 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
237 uint64_t NewVal = Mask << ShAmt->getValue();
238 SrcBits = MVT::getSizeInBits(Op.getValueType());
239 if (SrcBits != 64) NewVal &= (1ULL << SrcBits)-1;
240 return MaskedValueIsZero(Op.getOperand(0), NewVal, TLI);
244 // (ushl X, C1) & C2 == 0 iff X & (C2 >> C1) == 0
245 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
246 uint64_t NewVal = Mask >> ShAmt->getValue();
247 return MaskedValueIsZero(Op.getOperand(0), NewVal, TLI);
251 // (add X, Y) & C == 0 iff (X&C)|(Y&C) == 0 and all bits are low bits.
252 if ((Mask&(Mask+1)) == 0) { // All low bits
253 if (MaskedValueIsZero(Op.getOperand(0), Mask, TLI) &&
254 MaskedValueIsZero(Op.getOperand(1), Mask, TLI))
259 if (ConstantSDNode *CLHS = dyn_cast<ConstantSDNode>(Op.getOperand(0))) {
260 // We know that the top bits of C-X are clear if X contains less bits
261 // than C (i.e. no wrap-around can happen). For example, 20-X is
262 // positive if we can prove that X is >= 0 and < 16.
263 unsigned Bits = MVT::getSizeInBits(CLHS->getValueType(0));
264 if ((CLHS->getValue() & (1 << (Bits-1))) == 0) { // sign bit clear
265 unsigned NLZ = CountLeadingZeros_64(CLHS->getValue()+1);
266 uint64_t MaskV = (1ULL << (63-NLZ))-1;
267 if (MaskedValueIsZero(Op.getOperand(1), ~MaskV, TLI)) {
268 // High bits are clear this value is known to be >= C.
269 unsigned NLZ2 = CountLeadingZeros_64(CLHS->getValue());
270 if ((Mask & ((1ULL << (64-NLZ2))-1)) == 0)
279 // Bit counting instructions can not set the high bits of the result
280 // register. The max number of bits sets depends on the input.
281 return (Mask & (MVT::getSizeInBits(Op.getValueType())*2-1)) == 0;
287 // isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc
288 // that selects between the values 1 and 0, making it equivalent to a setcc.
289 // Also, set the incoming LHS, RHS, and CC references to the appropriate
290 // nodes based on the type of node we are checking. This simplifies life a
291 // bit for the callers.
292 static bool isSetCCEquivalent(SDOperand N, SDOperand &LHS, SDOperand &RHS,
294 if (N.getOpcode() == ISD::SETCC) {
295 LHS = N.getOperand(0);
296 RHS = N.getOperand(1);
297 CC = N.getOperand(2);
300 if (N.getOpcode() == ISD::SELECT_CC &&
301 N.getOperand(2).getOpcode() == ISD::Constant &&
302 N.getOperand(3).getOpcode() == ISD::Constant &&
303 cast<ConstantSDNode>(N.getOperand(2))->getValue() == 1 &&
304 cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) {
305 LHS = N.getOperand(0);
306 RHS = N.getOperand(1);
307 CC = N.getOperand(4);
313 // isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only
314 // one use. If this is true, it allows the users to invert the operation for
315 // free when it is profitable to do so.
316 static bool isOneUseSetCC(SDOperand N) {
317 SDOperand N0, N1, N2;
318 if (isSetCCEquivalent(N, N0, N1, N2) && N.Val->hasOneUse())
323 // FIXME: This should probably go in the ISD class rather than being duplicated
325 static bool isCommutativeBinOp(unsigned Opcode) {
331 case ISD::XOR: return true;
332 default: return false; // FIXME: Need commutative info for user ops!
336 void DAGCombiner::Run(bool RunningAfterLegalize) {
337 // set the instance variable, so that the various visit routines may use it.
338 AfterLegalize = RunningAfterLegalize;
340 // Add all the dag nodes to the worklist.
341 WorkList.insert(WorkList.end(), DAG.allnodes_begin(), DAG.allnodes_end());
343 // Create a dummy node (which is not added to allnodes), that adds a reference
344 // to the root node, preventing it from being deleted, and tracking any
345 // changes of the root.
346 HandleSDNode Dummy(DAG.getRoot());
348 // while the worklist isn't empty, inspect the node on the end of it and
349 // try and combine it.
350 while (!WorkList.empty()) {
351 SDNode *N = WorkList.back();
354 // If N has no uses, it is dead. Make sure to revisit all N's operands once
355 // N is deleted from the DAG, since they too may now be dead or may have a
356 // reduced number of uses, allowing other xforms.
357 if (N->use_empty() && N != &Dummy) {
358 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
359 WorkList.push_back(N->getOperand(i).Val);
361 removeFromWorkList(N);
366 SDOperand RV = visit(N);
369 // If we get back the same node we passed in, rather than a new node or
370 // zero, we know that the node must have defined multiple values and
371 // CombineTo was used. Since CombineTo takes care of the worklist
372 // mechanics for us, we have no work to do in this case.
374 DEBUG(std::cerr << "\nReplacing "; N->dump();
375 std::cerr << "\nWith: "; RV.Val->dump();
377 std::vector<SDNode*> NowDead;
378 DAG.ReplaceAllUsesWith(N, std::vector<SDOperand>(1, RV), &NowDead);
380 // Push the new node and any users onto the worklist
381 WorkList.push_back(RV.Val);
382 AddUsersToWorkList(RV.Val);
384 // Nodes can end up on the worklist more than once. Make sure we do
385 // not process a node that has been replaced.
386 removeFromWorkList(N);
387 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
388 removeFromWorkList(NowDead[i]);
390 // Finally, since the node is now dead, remove it from the graph.
396 // If the root changed (e.g. it was a dead load, update the root).
397 DAG.setRoot(Dummy.getValue());
400 SDOperand DAGCombiner::visit(SDNode *N) {
401 switch(N->getOpcode()) {
403 case ISD::TokenFactor: return visitTokenFactor(N);
404 case ISD::ADD: return visitADD(N);
405 case ISD::SUB: return visitSUB(N);
406 case ISD::MUL: return visitMUL(N);
407 case ISD::SDIV: return visitSDIV(N);
408 case ISD::UDIV: return visitUDIV(N);
409 case ISD::SREM: return visitSREM(N);
410 case ISD::UREM: return visitUREM(N);
411 case ISD::MULHU: return visitMULHU(N);
412 case ISD::MULHS: return visitMULHS(N);
413 case ISD::AND: return visitAND(N);
414 case ISD::OR: return visitOR(N);
415 case ISD::XOR: return visitXOR(N);
416 case ISD::SHL: return visitSHL(N);
417 case ISD::SRA: return visitSRA(N);
418 case ISD::SRL: return visitSRL(N);
419 case ISD::CTLZ: return visitCTLZ(N);
420 case ISD::CTTZ: return visitCTTZ(N);
421 case ISD::CTPOP: return visitCTPOP(N);
422 case ISD::SELECT: return visitSELECT(N);
423 case ISD::SELECT_CC: return visitSELECT_CC(N);
424 case ISD::SETCC: return visitSETCC(N);
425 case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N);
426 case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N);
427 case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N);
428 case ISD::TRUNCATE: return visitTRUNCATE(N);
429 case ISD::FADD: return visitFADD(N);
430 case ISD::FSUB: return visitFSUB(N);
431 case ISD::FMUL: return visitFMUL(N);
432 case ISD::FDIV: return visitFDIV(N);
433 case ISD::FREM: return visitFREM(N);
434 case ISD::SINT_TO_FP: return visitSINT_TO_FP(N);
435 case ISD::UINT_TO_FP: return visitUINT_TO_FP(N);
436 case ISD::FP_TO_SINT: return visitFP_TO_SINT(N);
437 case ISD::FP_TO_UINT: return visitFP_TO_UINT(N);
438 case ISD::FP_ROUND: return visitFP_ROUND(N);
439 case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N);
440 case ISD::FP_EXTEND: return visitFP_EXTEND(N);
441 case ISD::FNEG: return visitFNEG(N);
442 case ISD::FABS: return visitFABS(N);
443 case ISD::BRCOND: return visitBRCOND(N);
444 case ISD::BRCONDTWOWAY: return visitBRCONDTWOWAY(N);
445 case ISD::BR_CC: return visitBR_CC(N);
446 case ISD::BRTWOWAY_CC: return visitBRTWOWAY_CC(N);
447 case ISD::LOAD: return visitLOAD(N);
448 case ISD::STORE: return visitSTORE(N);
453 SDOperand DAGCombiner::visitTokenFactor(SDNode *N) {
454 std::vector<SDOperand> Ops;
455 bool Changed = false;
457 // If the token factor has two operands and one is the entry token, replace
458 // the token factor with the other operand.
459 if (N->getNumOperands() == 2) {
460 if (N->getOperand(0).getOpcode() == ISD::EntryToken)
461 return N->getOperand(1);
462 if (N->getOperand(1).getOpcode() == ISD::EntryToken)
463 return N->getOperand(0);
465 // fold (tokenfactor (tokenfactor)) -> tokenfactor
466 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
467 SDOperand Op = N->getOperand(i);
468 if (Op.getOpcode() == ISD::TokenFactor && Op.hasOneUse()) {
470 for (unsigned j = 0, e = Op.getNumOperands(); j != e; ++j)
471 Ops.push_back(Op.getOperand(j));
477 return DAG.getNode(ISD::TokenFactor, MVT::Other, Ops);
481 SDOperand DAGCombiner::visitADD(SDNode *N) {
482 SDOperand N0 = N->getOperand(0);
483 SDOperand N1 = N->getOperand(1);
484 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
485 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
486 MVT::ValueType VT = N0.getValueType();
488 // fold (add c1, c2) -> c1+c2
490 return DAG.getConstant(N0C->getValue() + N1C->getValue(), VT);
491 // canonicalize constant to RHS
496 // fold (add x, 0) -> x
497 if (N1C && N1C->isNullValue())
499 // fold (add (add x, c1), c2) -> (add x, c1+c2)
500 if (N1C && N0.getOpcode() == ISD::ADD) {
501 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
502 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
504 return DAG.getNode(ISD::ADD, VT, N0.getOperand(1),
505 DAG.getConstant(N1C->getValue()+N00C->getValue(), VT));
507 return DAG.getNode(ISD::ADD, VT, N0.getOperand(0),
508 DAG.getConstant(N1C->getValue()+N01C->getValue(), VT));
510 // fold ((0-A) + B) -> B-A
511 if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) &&
512 cast<ConstantSDNode>(N0.getOperand(0))->isNullValue())
513 return DAG.getNode(ISD::SUB, VT, N1, N0.getOperand(1));
514 // fold (A + (0-B)) -> A-B
515 if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) &&
516 cast<ConstantSDNode>(N1.getOperand(0))->isNullValue())
517 return DAG.getNode(ISD::SUB, VT, N0, N1.getOperand(1));
518 // fold (A+(B-A)) -> B
519 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1))
520 return N1.getOperand(0);
524 SDOperand DAGCombiner::visitSUB(SDNode *N) {
525 SDOperand N0 = N->getOperand(0);
526 SDOperand N1 = N->getOperand(1);
527 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
528 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
530 // fold (sub c1, c2) -> c1-c2
532 return DAG.getConstant(N0C->getValue() - N1C->getValue(),
534 // fold (sub x, c) -> (add x, -c)
536 return DAG.getNode(ISD::ADD, N0.getValueType(), N0,
537 DAG.getConstant(-N1C->getValue(), N0.getValueType()));
540 if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1)
541 return N0.getOperand(1);
543 if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1)
544 return N0.getOperand(0);
548 SDOperand DAGCombiner::visitMUL(SDNode *N) {
549 SDOperand N0 = N->getOperand(0);
550 SDOperand N1 = N->getOperand(1);
551 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
552 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
553 MVT::ValueType VT = N0.getValueType();
555 // fold (mul c1, c2) -> c1*c2
557 return DAG.getConstant(N0C->getValue() * N1C->getValue(),
559 // canonicalize constant to RHS
564 // fold (mul x, 0) -> 0
565 if (N1C && N1C->isNullValue())
567 // fold (mul x, -1) -> 0-x
568 if (N1C && N1C->isAllOnesValue())
569 return DAG.getNode(ISD::SUB, N->getValueType(0),
570 DAG.getConstant(0, N->getValueType(0)), N0);
571 // fold (mul x, (1 << c)) -> x << c
572 if (N1C && isPowerOf2_64(N1C->getValue()))
573 return DAG.getNode(ISD::SHL, N->getValueType(0), N0,
574 DAG.getConstant(Log2_64(N1C->getValue()),
575 TLI.getShiftAmountTy()));
576 // fold (mul (mul x, c1), c2) -> (mul x, c1*c2)
577 if (N1C && N0.getOpcode() == ISD::MUL) {
578 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
579 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
581 return DAG.getNode(ISD::MUL, VT, N0.getOperand(1),
582 DAG.getConstant(N1C->getValue()*N00C->getValue(), VT));
584 return DAG.getNode(ISD::MUL, VT, N0.getOperand(0),
585 DAG.getConstant(N1C->getValue()*N01C->getValue(), VT));
590 SDOperand DAGCombiner::visitSDIV(SDNode *N) {
591 SDOperand N0 = N->getOperand(0);
592 SDOperand N1 = N->getOperand(1);
593 MVT::ValueType VT = N->getValueType(0);
594 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
595 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
597 // fold (sdiv c1, c2) -> c1/c2
598 if (N0C && N1C && !N1C->isNullValue())
599 return DAG.getConstant(N0C->getSignExtended() / N1C->getSignExtended(),
601 // If we know the sign bits of both operands are zero, strength reduce to a
602 // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2
603 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1);
604 if (MaskedValueIsZero(N1, SignBit, TLI) &&
605 MaskedValueIsZero(N0, SignBit, TLI))
606 return DAG.getNode(ISD::UDIV, N1.getValueType(), N0, N1);
610 SDOperand DAGCombiner::visitUDIV(SDNode *N) {
611 SDOperand N0 = N->getOperand(0);
612 SDOperand N1 = N->getOperand(1);
613 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
614 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
616 // fold (udiv c1, c2) -> c1/c2
617 if (N0C && N1C && !N1C->isNullValue())
618 return DAG.getConstant(N0C->getValue() / N1C->getValue(),
620 // fold (udiv x, (1 << c)) -> x >>u c
621 if (N1C && isPowerOf2_64(N1C->getValue()))
622 return DAG.getNode(ISD::SRL, N->getValueType(0), N0,
623 DAG.getConstant(Log2_64(N1C->getValue()),
624 TLI.getShiftAmountTy()));
628 SDOperand DAGCombiner::visitSREM(SDNode *N) {
629 SDOperand N0 = N->getOperand(0);
630 SDOperand N1 = N->getOperand(1);
631 MVT::ValueType VT = N->getValueType(0);
632 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
633 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
635 // fold (srem c1, c2) -> c1%c2
636 if (N0C && N1C && !N1C->isNullValue())
637 return DAG.getConstant(N0C->getSignExtended() % N1C->getSignExtended(),
639 // If we know the sign bits of both operands are zero, strength reduce to a
640 // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15
641 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1);
642 if (MaskedValueIsZero(N1, SignBit, TLI) &&
643 MaskedValueIsZero(N0, SignBit, TLI))
644 return DAG.getNode(ISD::UREM, N1.getValueType(), N0, N1);
648 SDOperand DAGCombiner::visitUREM(SDNode *N) {
649 SDOperand N0 = N->getOperand(0);
650 SDOperand N1 = N->getOperand(1);
651 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
652 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
654 // fold (urem c1, c2) -> c1%c2
655 if (N0C && N1C && !N1C->isNullValue())
656 return DAG.getConstant(N0C->getValue() % N1C->getValue(),
658 // fold (urem x, pow2) -> (and x, pow2-1)
659 if (N1C && !N1C->isNullValue() && isPowerOf2_64(N1C->getValue()))
660 return DAG.getNode(ISD::AND, N0.getValueType(), N0,
661 DAG.getConstant(N1C->getValue()-1, N1.getValueType()));
665 SDOperand DAGCombiner::visitMULHS(SDNode *N) {
666 SDOperand N0 = N->getOperand(0);
667 SDOperand N1 = N->getOperand(1);
668 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
670 // fold (mulhs x, 0) -> 0
671 if (N1C && N1C->isNullValue())
673 // fold (mulhs x, 1) -> (sra x, size(x)-1)
674 if (N1C && N1C->getValue() == 1)
675 return DAG.getNode(ISD::SRA, N0.getValueType(), N0,
676 DAG.getConstant(MVT::getSizeInBits(N0.getValueType())-1,
677 TLI.getShiftAmountTy()));
681 SDOperand DAGCombiner::visitMULHU(SDNode *N) {
682 SDOperand N0 = N->getOperand(0);
683 SDOperand N1 = N->getOperand(1);
684 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
686 // fold (mulhu x, 0) -> 0
687 if (N1C && N1C->isNullValue())
689 // fold (mulhu x, 1) -> 0
690 if (N1C && N1C->getValue() == 1)
691 return DAG.getConstant(0, N0.getValueType());
695 SDOperand DAGCombiner::visitAND(SDNode *N) {
696 SDOperand N0 = N->getOperand(0);
697 SDOperand N1 = N->getOperand(1);
698 SDOperand LL, LR, RL, RR, CC0, CC1;
699 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
700 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
701 MVT::ValueType VT = N1.getValueType();
702 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
704 // fold (and c1, c2) -> c1&c2
706 return DAG.getConstant(N0C->getValue() & N1C->getValue(), VT);
707 // canonicalize constant to RHS
712 // fold (and x, -1) -> x
713 if (N1C && N1C->isAllOnesValue())
715 // if (and x, c) is known to be zero, return 0
716 if (N1C && MaskedValueIsZero(SDOperand(N, 0), ~0ULL >> (64-OpSizeInBits),TLI))
717 return DAG.getConstant(0, VT);
718 // fold (and x, c) -> x iff (x & ~c) == 0
719 if (N1C && MaskedValueIsZero(N0,~N1C->getValue() & (~0ULL>>(64-OpSizeInBits)),
722 // fold (and (and x, c1), c2) -> (and x, c1^c2)
723 if (N1C && N0.getOpcode() == ISD::AND) {
724 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
725 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
727 return DAG.getNode(ISD::AND, VT, N0.getOperand(1),
728 DAG.getConstant(N1C->getValue()&N00C->getValue(), VT));
730 return DAG.getNode(ISD::AND, VT, N0.getOperand(0),
731 DAG.getConstant(N1C->getValue()&N01C->getValue(), VT));
733 // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1)
734 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG) {
735 unsigned ExtendBits =
736 MVT::getSizeInBits(cast<VTSDNode>(N0.getOperand(1))->getVT());
737 if ((N1C->getValue() & (~0ULL << ExtendBits)) == 0)
738 return DAG.getNode(ISD::AND, VT, N0.getOperand(0), N1);
740 // fold (and (or x, 0xFFFF), 0xFF) -> 0xFF
741 if (N0.getOpcode() == ISD::OR && N1C)
742 if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
743 if ((ORI->getValue() & N1C->getValue()) == N1C->getValue())
745 // fold (and (setcc x), (setcc y)) -> (setcc (and x, y))
746 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
747 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
748 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
750 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
751 MVT::isInteger(LL.getValueType())) {
752 // fold (X == 0) & (Y == 0) -> (X|Y == 0)
753 if (cast<ConstantSDNode>(LR)->getValue() == 0 && Op1 == ISD::SETEQ) {
754 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
755 WorkList.push_back(ORNode.Val);
756 return DAG.getSetCC(VT, ORNode, LR, Op1);
758 // fold (X == -1) & (Y == -1) -> (X&Y == -1)
759 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) {
760 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL);
761 WorkList.push_back(ANDNode.Val);
762 return DAG.getSetCC(VT, ANDNode, LR, Op1);
764 // fold (X > -1) & (Y > -1) -> (X|Y > -1)
765 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) {
766 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
767 WorkList.push_back(ORNode.Val);
768 return DAG.getSetCC(VT, ORNode, LR, Op1);
771 // canonicalize equivalent to ll == rl
772 if (LL == RR && LR == RL) {
773 Op1 = ISD::getSetCCSwappedOperands(Op1);
776 if (LL == RL && LR == RR) {
777 bool isInteger = MVT::isInteger(LL.getValueType());
778 ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger);
779 if (Result != ISD::SETCC_INVALID)
780 return DAG.getSetCC(N0.getValueType(), LL, LR, Result);
783 // fold (and (zext x), (zext y)) -> (zext (and x, y))
784 if (N0.getOpcode() == ISD::ZERO_EXTEND &&
785 N1.getOpcode() == ISD::ZERO_EXTEND &&
786 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) {
787 SDOperand ANDNode = DAG.getNode(ISD::AND, N0.getOperand(0).getValueType(),
788 N0.getOperand(0), N1.getOperand(0));
789 WorkList.push_back(ANDNode.Val);
790 return DAG.getNode(ISD::ZERO_EXTEND, VT, ANDNode);
792 // fold (and (shl/srl x), (shl/srl y)) -> (shl/srl (and x, y))
793 if (((N0.getOpcode() == ISD::SHL && N1.getOpcode() == ISD::SHL) ||
794 (N0.getOpcode() == ISD::SRL && N1.getOpcode() == ISD::SRL)) &&
795 N0.getOperand(1) == N1.getOperand(1)) {
796 SDOperand ANDNode = DAG.getNode(ISD::AND, N0.getOperand(0).getValueType(),
797 N0.getOperand(0), N1.getOperand(0));
798 WorkList.push_back(ANDNode.Val);
799 return DAG.getNode(N0.getOpcode(), VT, ANDNode, N0.getOperand(1));
801 // fold (zext_inreg (extload x)) -> (zextload x)
802 if (N1C && N0.getOpcode() == ISD::EXTLOAD) {
803 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
804 // If the type of the zext_inreg and the extload match, and we're running
805 // before Legalize, or the resulting zextload is legal on the target, then
806 // go ahead and do the fold.
807 if ((N1C->getValue() == (1ULL << MVT::getSizeInBits(EVT))-1) &&
808 (!AfterLegalize || TLI.isOperationLegal(ISD::ZEXTLOAD, EVT))) {
809 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
810 N0.getOperand(1), N0.getOperand(2),
812 WorkList.push_back(N);
813 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
817 // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use
818 if (N1C && N0.getOpcode() == ISD::SEXTLOAD && N0.Val->hasNUsesOfValue(1, 0)) {
819 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
820 // If the type of the zext_inreg and the extload match, and we're running
821 // before Legalize, or the resulting zextload is legal on the target, then
822 // go ahead and do the fold.
823 if ((N1C->getValue() == (1ULL << MVT::getSizeInBits(EVT))-1) &&
825 TargetLowering::Legal == TLI.getOperationAction(ISD::ZEXTLOAD, EVT))) {
826 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
827 N0.getOperand(1), N0.getOperand(2),
829 WorkList.push_back(N);
830 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
837 SDOperand DAGCombiner::visitOR(SDNode *N) {
838 SDOperand N0 = N->getOperand(0);
839 SDOperand N1 = N->getOperand(1);
840 SDOperand LL, LR, RL, RR, CC0, CC1;
841 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
842 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
843 MVT::ValueType VT = N1.getValueType();
844 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
846 // fold (or c1, c2) -> c1|c2
848 return DAG.getConstant(N0C->getValue() | N1C->getValue(),
850 // canonicalize constant to RHS
855 // fold (or x, 0) -> x
856 if (N1C && N1C->isNullValue())
858 // fold (or x, -1) -> -1
859 if (N1C && N1C->isAllOnesValue())
861 // fold (or x, c) -> c iff (x & ~c) == 0
862 if (N1C && MaskedValueIsZero(N0,~N1C->getValue() & (~0ULL>>(64-OpSizeInBits)),
865 // fold (or (or x, c1), c2) -> (or x, c1|c2)
866 if (N1C && N0.getOpcode() == ISD::OR) {
867 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
868 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
870 return DAG.getNode(ISD::OR, VT, N0.getOperand(1),
871 DAG.getConstant(N1C->getValue()|N00C->getValue(), VT));
873 return DAG.getNode(ISD::OR, VT, N0.getOperand(0),
874 DAG.getConstant(N1C->getValue()|N01C->getValue(), VT));
876 // fold (or (setcc x), (setcc y)) -> (setcc (or x, y))
877 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
878 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
879 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
881 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
882 MVT::isInteger(LL.getValueType())) {
883 // fold (X != 0) | (Y != 0) -> (X|Y != 0)
884 // fold (X < 0) | (Y < 0) -> (X|Y < 0)
885 if (cast<ConstantSDNode>(LR)->getValue() == 0 &&
886 (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) {
887 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
888 WorkList.push_back(ORNode.Val);
889 return DAG.getSetCC(VT, ORNode, LR, Op1);
891 // fold (X != -1) | (Y != -1) -> (X&Y != -1)
892 // fold (X > -1) | (Y > -1) -> (X&Y > -1)
893 if (cast<ConstantSDNode>(LR)->isAllOnesValue() &&
894 (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) {
895 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL);
896 WorkList.push_back(ANDNode.Val);
897 return DAG.getSetCC(VT, ANDNode, LR, Op1);
900 // canonicalize equivalent to ll == rl
901 if (LL == RR && LR == RL) {
902 Op1 = ISD::getSetCCSwappedOperands(Op1);
905 if (LL == RL && LR == RR) {
906 bool isInteger = MVT::isInteger(LL.getValueType());
907 ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger);
908 if (Result != ISD::SETCC_INVALID)
909 return DAG.getSetCC(N0.getValueType(), LL, LR, Result);
912 // fold (or (zext x), (zext y)) -> (zext (or x, y))
913 if (N0.getOpcode() == ISD::ZERO_EXTEND &&
914 N1.getOpcode() == ISD::ZERO_EXTEND &&
915 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) {
916 SDOperand ORNode = DAG.getNode(ISD::OR, N0.getOperand(0).getValueType(),
917 N0.getOperand(0), N1.getOperand(0));
918 WorkList.push_back(ORNode.Val);
919 return DAG.getNode(ISD::ZERO_EXTEND, VT, ORNode);
924 SDOperand DAGCombiner::visitXOR(SDNode *N) {
925 SDOperand N0 = N->getOperand(0);
926 SDOperand N1 = N->getOperand(1);
927 SDOperand LHS, RHS, CC;
928 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
929 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
930 MVT::ValueType VT = N0.getValueType();
932 // fold (xor c1, c2) -> c1^c2
934 return DAG.getConstant(N0C->getValue() ^ N1C->getValue(), VT);
935 // canonicalize constant to RHS
940 // fold (xor x, 0) -> x
941 if (N1C && N1C->isNullValue())
943 // fold !(x cc y) -> (x !cc y)
944 if (N1C && N1C->getValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) {
945 bool isInt = MVT::isInteger(LHS.getValueType());
946 ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(),
948 if (N0.getOpcode() == ISD::SETCC)
949 return DAG.getSetCC(VT, LHS, RHS, NotCC);
950 if (N0.getOpcode() == ISD::SELECT_CC)
951 return DAG.getSelectCC(LHS, RHS, N0.getOperand(2),N0.getOperand(3),NotCC);
952 assert(0 && "Unhandled SetCC Equivalent!");
955 // fold !(x or y) -> (!x and !y) iff x or y are setcc
956 if (N1C && N1C->getValue() == 1 &&
957 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
958 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1);
959 if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) {
960 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
961 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS
962 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS
963 WorkList.push_back(LHS.Val); WorkList.push_back(RHS.Val);
964 return DAG.getNode(NewOpcode, VT, LHS, RHS);
967 // fold !(x or y) -> (!x and !y) iff x or y are constants
968 if (N1C && N1C->isAllOnesValue() &&
969 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
970 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1);
971 if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) {
972 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
973 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS
974 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS
975 WorkList.push_back(LHS.Val); WorkList.push_back(RHS.Val);
976 return DAG.getNode(NewOpcode, VT, LHS, RHS);
979 // fold (xor (xor x, c1), c2) -> (xor x, c1^c2)
980 if (N1C && N0.getOpcode() == ISD::XOR) {
981 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
982 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
984 return DAG.getNode(ISD::XOR, VT, N0.getOperand(1),
985 DAG.getConstant(N1C->getValue()^N00C->getValue(), VT));
987 return DAG.getNode(ISD::XOR, VT, N0.getOperand(0),
988 DAG.getConstant(N1C->getValue()^N01C->getValue(), VT));
990 // fold (xor x, x) -> 0
992 return DAG.getConstant(0, VT);
993 // fold (xor (zext x), (zext y)) -> (zext (xor x, y))
994 if (N0.getOpcode() == ISD::ZERO_EXTEND &&
995 N1.getOpcode() == ISD::ZERO_EXTEND &&
996 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) {
997 SDOperand XORNode = DAG.getNode(ISD::XOR, N0.getOperand(0).getValueType(),
998 N0.getOperand(0), N1.getOperand(0));
999 WorkList.push_back(XORNode.Val);
1000 return DAG.getNode(ISD::ZERO_EXTEND, VT, XORNode);
1005 SDOperand DAGCombiner::visitSHL(SDNode *N) {
1006 SDOperand N0 = N->getOperand(0);
1007 SDOperand N1 = N->getOperand(1);
1008 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1009 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1010 MVT::ValueType VT = N0.getValueType();
1011 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1013 // fold (shl c1, c2) -> c1<<c2
1015 return DAG.getConstant(N0C->getValue() << N1C->getValue(), VT);
1016 // fold (shl 0, x) -> 0
1017 if (N0C && N0C->isNullValue())
1019 // fold (shl x, c >= size(x)) -> undef
1020 if (N1C && N1C->getValue() >= OpSizeInBits)
1021 return DAG.getNode(ISD::UNDEF, VT);
1022 // fold (shl x, 0) -> x
1023 if (N1C && N1C->isNullValue())
1025 // if (shl x, c) is known to be zero, return 0
1026 if (N1C && MaskedValueIsZero(SDOperand(N, 0), ~0ULL >> (64-OpSizeInBits),TLI))
1027 return DAG.getConstant(0, VT);
1028 // fold (shl (shl x, c1), c2) -> 0 or (shl x, c1+c2)
1029 if (N1C && N0.getOpcode() == ISD::SHL &&
1030 N0.getOperand(1).getOpcode() == ISD::Constant) {
1031 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1032 uint64_t c2 = N1C->getValue();
1033 if (c1 + c2 > OpSizeInBits)
1034 return DAG.getConstant(0, VT);
1035 return DAG.getNode(ISD::SHL, VT, N0.getOperand(0),
1036 DAG.getConstant(c1 + c2, N1.getValueType()));
1038 // fold (shl (srl x, c1), c2) -> (shl (and x, -1 << c1), c2-c1) or
1039 // (srl (and x, -1 << c1), c1-c2)
1040 if (N1C && N0.getOpcode() == ISD::SRL &&
1041 N0.getOperand(1).getOpcode() == ISD::Constant) {
1042 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1043 uint64_t c2 = N1C->getValue();
1044 SDOperand Mask = DAG.getNode(ISD::AND, VT, N0.getOperand(0),
1045 DAG.getConstant(~0ULL << c1, VT));
1047 return DAG.getNode(ISD::SHL, VT, Mask,
1048 DAG.getConstant(c2-c1, N1.getValueType()));
1050 return DAG.getNode(ISD::SRL, VT, Mask,
1051 DAG.getConstant(c1-c2, N1.getValueType()));
1053 // fold (shl (sra x, c1), c1) -> (and x, -1 << c1)
1054 if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1))
1055 return DAG.getNode(ISD::AND, VT, N0.getOperand(0),
1056 DAG.getConstant(~0ULL << N1C->getValue(), VT));
1060 SDOperand DAGCombiner::visitSRA(SDNode *N) {
1061 SDOperand N0 = N->getOperand(0);
1062 SDOperand N1 = N->getOperand(1);
1063 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1064 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1065 MVT::ValueType VT = N0.getValueType();
1066 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1068 // fold (sra c1, c2) -> c1>>c2
1070 return DAG.getConstant(N0C->getSignExtended() >> N1C->getValue(), VT);
1071 // fold (sra 0, x) -> 0
1072 if (N0C && N0C->isNullValue())
1074 // fold (sra -1, x) -> -1
1075 if (N0C && N0C->isAllOnesValue())
1077 // fold (sra x, c >= size(x)) -> undef
1078 if (N1C && N1C->getValue() >= OpSizeInBits)
1079 return DAG.getNode(ISD::UNDEF, VT);
1080 // fold (sra x, 0) -> x
1081 if (N1C && N1C->isNullValue())
1083 // If the sign bit is known to be zero, switch this to a SRL.
1084 if (MaskedValueIsZero(N0, (1ULL << (OpSizeInBits-1)), TLI))
1085 return DAG.getNode(ISD::SRL, VT, N0, N1);
1089 SDOperand DAGCombiner::visitSRL(SDNode *N) {
1090 SDOperand N0 = N->getOperand(0);
1091 SDOperand N1 = N->getOperand(1);
1092 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1093 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1094 MVT::ValueType VT = N0.getValueType();
1095 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1097 // fold (srl c1, c2) -> c1 >>u c2
1099 return DAG.getConstant(N0C->getValue() >> N1C->getValue(), VT);
1100 // fold (srl 0, x) -> 0
1101 if (N0C && N0C->isNullValue())
1103 // fold (srl x, c >= size(x)) -> undef
1104 if (N1C && N1C->getValue() >= OpSizeInBits)
1105 return DAG.getNode(ISD::UNDEF, VT);
1106 // fold (srl x, 0) -> x
1107 if (N1C && N1C->isNullValue())
1109 // if (srl x, c) is known to be zero, return 0
1110 if (N1C && MaskedValueIsZero(SDOperand(N, 0), ~0ULL >> (64-OpSizeInBits),TLI))
1111 return DAG.getConstant(0, VT);
1112 // fold (srl (srl x, c1), c2) -> 0 or (srl x, c1+c2)
1113 if (N1C && N0.getOpcode() == ISD::SRL &&
1114 N0.getOperand(1).getOpcode() == ISD::Constant) {
1115 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1116 uint64_t c2 = N1C->getValue();
1117 if (c1 + c2 > OpSizeInBits)
1118 return DAG.getConstant(0, VT);
1119 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0),
1120 DAG.getConstant(c1 + c2, N1.getValueType()));
1125 SDOperand DAGCombiner::visitCTLZ(SDNode *N) {
1126 SDOperand N0 = N->getOperand(0);
1127 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1129 // fold (ctlz c1) -> c2
1131 return DAG.getConstant(CountLeadingZeros_64(N0C->getValue()),
1136 SDOperand DAGCombiner::visitCTTZ(SDNode *N) {
1137 SDOperand N0 = N->getOperand(0);
1138 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1140 // fold (cttz c1) -> c2
1142 return DAG.getConstant(CountTrailingZeros_64(N0C->getValue()),
1147 SDOperand DAGCombiner::visitCTPOP(SDNode *N) {
1148 SDOperand N0 = N->getOperand(0);
1149 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1151 // fold (ctpop c1) -> c2
1153 return DAG.getConstant(CountPopulation_64(N0C->getValue()),
1158 SDOperand DAGCombiner::visitSELECT(SDNode *N) {
1159 SDOperand N0 = N->getOperand(0);
1160 SDOperand N1 = N->getOperand(1);
1161 SDOperand N2 = N->getOperand(2);
1162 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1163 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1164 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2);
1165 MVT::ValueType VT = N->getValueType(0);
1167 // fold select C, X, X -> X
1170 // fold select true, X, Y -> X
1171 if (N0C && !N0C->isNullValue())
1173 // fold select false, X, Y -> Y
1174 if (N0C && N0C->isNullValue())
1176 // fold select C, 1, X -> C | X
1177 if (MVT::i1 == VT && N1C && N1C->getValue() == 1)
1178 return DAG.getNode(ISD::OR, VT, N0, N2);
1179 // fold select C, 0, X -> ~C & X
1180 // FIXME: this should check for C type == X type, not i1?
1181 if (MVT::i1 == VT && N1C && N1C->isNullValue()) {
1182 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT));
1183 WorkList.push_back(XORNode.Val);
1184 return DAG.getNode(ISD::AND, VT, XORNode, N2);
1186 // fold select C, X, 1 -> ~C | X
1187 if (MVT::i1 == VT && N2C && N2C->getValue() == 1) {
1188 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT));
1189 WorkList.push_back(XORNode.Val);
1190 return DAG.getNode(ISD::OR, VT, XORNode, N1);
1192 // fold select C, X, 0 -> C & X
1193 // FIXME: this should check for C type == X type, not i1?
1194 if (MVT::i1 == VT && N2C && N2C->isNullValue())
1195 return DAG.getNode(ISD::AND, VT, N0, N1);
1196 // fold X ? X : Y --> X ? 1 : Y --> X | Y
1197 if (MVT::i1 == VT && N0 == N1)
1198 return DAG.getNode(ISD::OR, VT, N0, N2);
1199 // fold X ? Y : X --> X ? Y : 0 --> X & Y
1200 if (MVT::i1 == VT && N0 == N2)
1201 return DAG.getNode(ISD::AND, VT, N0, N1);
1202 // fold selects based on a setcc into other things, such as min/max/abs
1203 if (N0.getOpcode() == ISD::SETCC)
1204 return SimplifySelect(N0, N1, N2);
1208 SDOperand DAGCombiner::visitSELECT_CC(SDNode *N) {
1209 SDOperand N0 = N->getOperand(0);
1210 SDOperand N1 = N->getOperand(1);
1211 SDOperand N2 = N->getOperand(2);
1212 SDOperand N3 = N->getOperand(3);
1213 SDOperand N4 = N->getOperand(4);
1214 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1215 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1216 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2);
1217 ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get();
1219 // Determine if the condition we're dealing with is constant
1220 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false);
1221 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val);
1223 // fold select_cc lhs, rhs, x, x, cc -> x
1226 // fold select_cc into other things, such as min/max/abs
1227 return SimplifySelectCC(N0, N1, N2, N3, CC);
1230 SDOperand DAGCombiner::visitSETCC(SDNode *N) {
1231 return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1),
1232 cast<CondCodeSDNode>(N->getOperand(2))->get());
1235 SDOperand DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
1236 SDOperand N0 = N->getOperand(0);
1237 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1238 MVT::ValueType VT = N->getValueType(0);
1240 // fold (sext c1) -> c1
1242 return DAG.getConstant(N0C->getSignExtended(), VT);
1243 // fold (sext (sext x)) -> (sext x)
1244 if (N0.getOpcode() == ISD::SIGN_EXTEND)
1245 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0.getOperand(0));
1246 // fold (sext (sextload x)) -> (sextload x)
1247 if (N0.getOpcode() == ISD::SEXTLOAD && VT == N0.getValueType())
1249 // fold (sext (load x)) -> (sextload x)
1250 if (N0.getOpcode() == ISD::LOAD && N0.Val->hasNUsesOfValue(1, 0)) {
1251 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1252 N0.getOperand(1), N0.getOperand(2),
1254 CombineTo(N0.Val, ExtLoad, ExtLoad.getOperand(0));
1255 WorkList.push_back(N);
1261 SDOperand DAGCombiner::visitZERO_EXTEND(SDNode *N) {
1262 SDOperand N0 = N->getOperand(0);
1263 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1264 MVT::ValueType VT = N->getValueType(0);
1266 // fold (zext c1) -> c1
1268 return DAG.getConstant(N0C->getValue(), VT);
1269 // fold (zext (zext x)) -> (zext x)
1270 if (N0.getOpcode() == ISD::ZERO_EXTEND)
1271 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0.getOperand(0));
1275 SDOperand DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) {
1276 SDOperand N0 = N->getOperand(0);
1277 SDOperand N1 = N->getOperand(1);
1278 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1279 MVT::ValueType VT = N->getValueType(0);
1280 MVT::ValueType EVT = cast<VTSDNode>(N1)->getVT();
1281 unsigned EVTBits = MVT::getSizeInBits(EVT);
1283 // fold (sext_in_reg c1) -> c1
1285 SDOperand Truncate = DAG.getConstant(N0C->getValue(), EVT);
1286 return DAG.getNode(ISD::SIGN_EXTEND, VT, Truncate);
1288 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt1
1289 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
1290 cast<VTSDNode>(N0.getOperand(1))->getVT() < EVT) {
1293 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2
1294 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
1295 EVT < cast<VTSDNode>(N0.getOperand(1))->getVT()) {
1296 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), N1);
1298 // fold (sext_in_reg (assert_sext x)) -> (assert_sext x)
1299 if (N0.getOpcode() == ISD::AssertSext &&
1300 cast<VTSDNode>(N0.getOperand(1))->getVT() <= EVT) {
1303 // fold (sext_in_reg (sextload x)) -> (sextload x)
1304 if (N0.getOpcode() == ISD::SEXTLOAD &&
1305 cast<VTSDNode>(N0.getOperand(3))->getVT() <= EVT) {
1308 // fold (sext_in_reg (setcc x)) -> setcc x iff (setcc x) == 0 or -1
1309 if (N0.getOpcode() == ISD::SETCC &&
1310 TLI.getSetCCResultContents() ==
1311 TargetLowering::ZeroOrNegativeOneSetCCResult)
1313 // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is zero
1314 if (MaskedValueIsZero(N0, 1ULL << (EVTBits-1), TLI))
1315 return DAG.getNode(ISD::AND, N0.getValueType(), N0,
1316 DAG.getConstant(~0ULL >> (64-EVTBits), VT));
1317 // fold (sext_in_reg (srl x)) -> sra x
1318 if (N0.getOpcode() == ISD::SRL &&
1319 N0.getOperand(1).getOpcode() == ISD::Constant &&
1320 cast<ConstantSDNode>(N0.getOperand(1))->getValue() == EVTBits) {
1321 return DAG.getNode(ISD::SRA, N0.getValueType(), N0.getOperand(0),
1324 // fold (sext_inreg (extload x)) -> (sextload x)
1325 if (N0.getOpcode() == ISD::EXTLOAD &&
1326 EVT == cast<VTSDNode>(N0.getOperand(3))->getVT() &&
1328 (TargetLowering::Legal == TLI.getOperationAction(ISD::SEXTLOAD, EVT)))) {
1329 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1330 N0.getOperand(1), N0.getOperand(2),
1332 CombineTo(N0.Val, ExtLoad, ExtLoad.getOperand(0));
1333 WorkList.push_back(N);
1336 // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use
1337 if (N0.getOpcode() == ISD::ZEXTLOAD && N0.Val->hasNUsesOfValue(1, 0) &&
1338 EVT == cast<VTSDNode>(N0.getOperand(3))->getVT() &&
1340 (TargetLowering::Legal == TLI.getOperationAction(ISD::SEXTLOAD, EVT)))) {
1341 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1342 N0.getOperand(1), N0.getOperand(2),
1344 CombineTo(N0.Val, ExtLoad, ExtLoad.getOperand(0));
1345 WorkList.push_back(N);
1351 SDOperand DAGCombiner::visitTRUNCATE(SDNode *N) {
1352 SDOperand N0 = N->getOperand(0);
1353 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1354 MVT::ValueType VT = N->getValueType(0);
1357 if (N0.getValueType() == N->getValueType(0))
1359 // fold (truncate c1) -> c1
1361 return DAG.getConstant(N0C->getValue(), VT);
1362 // fold (truncate (truncate x)) -> (truncate x)
1363 if (N0.getOpcode() == ISD::TRUNCATE)
1364 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0));
1365 // fold (truncate (ext x)) -> (ext x) or (truncate x) or x
1366 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND){
1367 if (N0.getValueType() < VT)
1368 // if the source is smaller than the dest, we still need an extend
1369 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0));
1370 else if (N0.getValueType() > VT)
1371 // if the source is larger than the dest, than we just need the truncate
1372 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0));
1374 // if the source and dest are the same type, we can drop both the extend
1376 return N0.getOperand(0);
1378 // fold (truncate (load x)) -> (smaller load x)
1379 if (N0.getOpcode() == ISD::LOAD && N0.Val->hasNUsesOfValue(1, 0)) {
1380 assert(MVT::getSizeInBits(N0.getValueType()) > MVT::getSizeInBits(VT) &&
1381 "Cannot truncate to larger type!");
1382 MVT::ValueType PtrType = N0.getOperand(1).getValueType();
1383 // For big endian targets, we need to add an offset to the pointer to load
1384 // the correct bytes. For little endian systems, we merely need to read
1385 // fewer bytes from the same pointer.
1387 (MVT::getSizeInBits(N0.getValueType()) - MVT::getSizeInBits(VT)) / 8;
1388 SDOperand NewPtr = TLI.isLittleEndian() ? N0.getOperand(1) :
1389 DAG.getNode(ISD::ADD, PtrType, N0.getOperand(1),
1390 DAG.getConstant(PtrOff, PtrType));
1391 WorkList.push_back(NewPtr.Val);
1392 SDOperand Load = DAG.getLoad(VT, N0.getOperand(0), NewPtr,N0.getOperand(2));
1393 CombineTo(N0.Val, Load, Load.getOperand(0));
1394 WorkList.push_back(N);
1400 SDOperand DAGCombiner::visitFADD(SDNode *N) {
1401 SDOperand N0 = N->getOperand(0);
1402 SDOperand N1 = N->getOperand(1);
1403 MVT::ValueType VT = N->getValueType(0);
1405 if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0))
1406 if (ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1)) {
1407 // fold floating point (fadd c1, c2)
1408 return DAG.getConstantFP(N0CFP->getValue() + N1CFP->getValue(),
1409 N->getValueType(0));
1411 // fold (A + (-B)) -> A-B
1412 if (N1.getOpcode() == ISD::FNEG)
1413 return DAG.getNode(ISD::FSUB, VT, N0, N1.getOperand(0));
1415 // fold ((-A) + B) -> B-A
1416 if (N0.getOpcode() == ISD::FNEG)
1417 return DAG.getNode(ISD::FSUB, VT, N1, N0.getOperand(0));
1422 SDOperand DAGCombiner::visitFSUB(SDNode *N) {
1423 SDOperand N0 = N->getOperand(0);
1424 SDOperand N1 = N->getOperand(1);
1425 MVT::ValueType VT = N->getValueType(0);
1427 if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0))
1428 if (ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1)) {
1429 // fold floating point (fsub c1, c2)
1430 return DAG.getConstantFP(N0CFP->getValue() - N1CFP->getValue(),
1431 N->getValueType(0));
1433 // fold (A-(-B)) -> A+B
1434 if (N1.getOpcode() == ISD::FNEG)
1435 return DAG.getNode(ISD::FADD, N0.getValueType(), N0, N1.getOperand(0));
1440 SDOperand DAGCombiner::visitFMUL(SDNode *N) {
1441 SDOperand N0 = N->getOperand(0);
1442 SDOperand N1 = N->getOperand(1);
1443 MVT::ValueType VT = N->getValueType(0);
1445 if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0))
1446 if (ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1)) {
1447 // fold floating point (fmul c1, c2)
1448 return DAG.getConstantFP(N0CFP->getValue() * N1CFP->getValue(),
1449 N->getValueType(0));
1454 SDOperand DAGCombiner::visitFDIV(SDNode *N) {
1455 SDOperand N0 = N->getOperand(0);
1456 SDOperand N1 = N->getOperand(1);
1457 MVT::ValueType VT = N->getValueType(0);
1459 if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0))
1460 if (ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1)) {
1461 // fold floating point (fdiv c1, c2)
1462 return DAG.getConstantFP(N0CFP->getValue() / N1CFP->getValue(),
1463 N->getValueType(0));
1468 SDOperand DAGCombiner::visitFREM(SDNode *N) {
1469 SDOperand N0 = N->getOperand(0);
1470 SDOperand N1 = N->getOperand(1);
1471 MVT::ValueType VT = N->getValueType(0);
1473 if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0))
1474 if (ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1)) {
1475 // fold floating point (frem c1, c2) -> fmod(c1, c2)
1476 return DAG.getConstantFP(fmod(N0CFP->getValue(),N1CFP->getValue()),
1477 N->getValueType(0));
1483 SDOperand DAGCombiner::visitSINT_TO_FP(SDNode *N) {
1484 SDOperand N0 = N->getOperand(0);
1485 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1487 // fold (sint_to_fp c1) -> c1fp
1489 return DAG.getConstantFP(N0C->getSignExtended(), N->getValueType(0));
1493 SDOperand DAGCombiner::visitUINT_TO_FP(SDNode *N) {
1494 SDOperand N0 = N->getOperand(0);
1495 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1497 // fold (uint_to_fp c1) -> c1fp
1499 return DAG.getConstantFP(N0C->getValue(), N->getValueType(0));
1503 SDOperand DAGCombiner::visitFP_TO_SINT(SDNode *N) {
1504 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
1506 // fold (fp_to_sint c1fp) -> c1
1508 return DAG.getConstant((int64_t)N0CFP->getValue(), N->getValueType(0));
1512 SDOperand DAGCombiner::visitFP_TO_UINT(SDNode *N) {
1513 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
1515 // fold (fp_to_uint c1fp) -> c1
1517 return DAG.getConstant((uint64_t)N0CFP->getValue(), N->getValueType(0));
1521 SDOperand DAGCombiner::visitFP_ROUND(SDNode *N) {
1522 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
1524 // fold (fp_round c1fp) -> c1fp
1526 return DAG.getConstantFP(N0CFP->getValue(), N->getValueType(0));
1530 SDOperand DAGCombiner::visitFP_ROUND_INREG(SDNode *N) {
1531 SDOperand N0 = N->getOperand(0);
1532 MVT::ValueType VT = N->getValueType(0);
1533 MVT::ValueType EVT = cast<VTSDNode>(N->getOperand(1))->getVT();
1534 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
1536 // fold (fp_round_inreg c1fp) -> c1fp
1538 SDOperand Round = DAG.getConstantFP(N0CFP->getValue(), EVT);
1539 return DAG.getNode(ISD::FP_EXTEND, VT, Round);
1544 SDOperand DAGCombiner::visitFP_EXTEND(SDNode *N) {
1545 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
1547 // fold (fp_extend c1fp) -> c1fp
1549 return DAG.getConstantFP(N0CFP->getValue(), N->getValueType(0));
1553 SDOperand DAGCombiner::visitFNEG(SDNode *N) {
1554 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
1555 // fold (neg c1) -> -c1
1557 return DAG.getConstantFP(-N0CFP->getValue(), N->getValueType(0));
1558 // fold (neg (sub x, y)) -> (sub y, x)
1559 if (N->getOperand(0).getOpcode() == ISD::SUB)
1560 return DAG.getNode(ISD::SUB, N->getValueType(0), N->getOperand(1),
1562 // fold (neg (neg x)) -> x
1563 if (N->getOperand(0).getOpcode() == ISD::FNEG)
1564 return N->getOperand(0).getOperand(0);
1568 SDOperand DAGCombiner::visitFABS(SDNode *N) {
1569 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0));
1570 // fold (fabs c1) -> fabs(c1)
1572 return DAG.getConstantFP(fabs(N0CFP->getValue()), N->getValueType(0));
1573 // fold (fabs (fabs x)) -> (fabs x)
1574 if (N->getOperand(0).getOpcode() == ISD::FABS)
1575 return N->getOperand(0);
1576 // fold (fabs (fneg x)) -> (fabs x)
1577 if (N->getOperand(0).getOpcode() == ISD::FNEG)
1578 return DAG.getNode(ISD::FABS, N->getValueType(0),
1579 N->getOperand(0).getOperand(0));
1583 SDOperand DAGCombiner::visitBRCOND(SDNode *N) {
1584 SDOperand Chain = N->getOperand(0);
1585 SDOperand N1 = N->getOperand(1);
1586 SDOperand N2 = N->getOperand(2);
1587 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1589 // never taken branch, fold to chain
1590 if (N1C && N1C->isNullValue())
1592 // unconditional branch
1593 if (N1C && N1C->getValue() == 1)
1594 return DAG.getNode(ISD::BR, MVT::Other, Chain, N2);
1598 SDOperand DAGCombiner::visitBRCONDTWOWAY(SDNode *N) {
1599 SDOperand Chain = N->getOperand(0);
1600 SDOperand N1 = N->getOperand(1);
1601 SDOperand N2 = N->getOperand(2);
1602 SDOperand N3 = N->getOperand(3);
1603 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1605 // unconditional branch to true mbb
1606 if (N1C && N1C->getValue() == 1)
1607 return DAG.getNode(ISD::BR, MVT::Other, Chain, N2);
1608 // unconditional branch to false mbb
1609 if (N1C && N1C->isNullValue())
1610 return DAG.getNode(ISD::BR, MVT::Other, Chain, N3);
1614 // Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB.
1616 SDOperand DAGCombiner::visitBR_CC(SDNode *N) {
1617 CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1));
1618 SDOperand CondLHS = N->getOperand(2), CondRHS = N->getOperand(3);
1620 // Use SimplifySetCC to simplify SETCC's.
1621 SDOperand Simp = SimplifySetCC(MVT::i1, CondLHS, CondRHS, CC->get(), false);
1622 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(Simp.Val);
1624 // fold br_cc true, dest -> br dest (unconditional branch)
1625 if (SCCC && SCCC->getValue())
1626 return DAG.getNode(ISD::BR, MVT::Other, N->getOperand(0),
1628 // fold br_cc false, dest -> unconditional fall through
1629 if (SCCC && SCCC->isNullValue())
1630 return N->getOperand(0);
1631 // fold to a simpler setcc
1632 if (Simp.Val && Simp.getOpcode() == ISD::SETCC)
1633 return DAG.getNode(ISD::BR_CC, MVT::Other, N->getOperand(0),
1634 Simp.getOperand(2), Simp.getOperand(0),
1635 Simp.getOperand(1), N->getOperand(4));
1639 SDOperand DAGCombiner::visitBRTWOWAY_CC(SDNode *N) {
1640 SDOperand Chain = N->getOperand(0);
1641 SDOperand CCN = N->getOperand(1);
1642 SDOperand LHS = N->getOperand(2);
1643 SDOperand RHS = N->getOperand(3);
1644 SDOperand N4 = N->getOperand(4);
1645 SDOperand N5 = N->getOperand(5);
1647 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), LHS, RHS,
1648 cast<CondCodeSDNode>(CCN)->get(), false);
1649 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val);
1651 // fold select_cc lhs, rhs, x, x, cc -> x
1653 return DAG.getNode(ISD::BR, MVT::Other, Chain, N4);
1654 // fold select_cc true, x, y -> x
1655 if (SCCC && SCCC->getValue())
1656 return DAG.getNode(ISD::BR, MVT::Other, Chain, N4);
1657 // fold select_cc false, x, y -> y
1658 if (SCCC && SCCC->isNullValue())
1659 return DAG.getNode(ISD::BR, MVT::Other, Chain, N5);
1660 // fold to a simpler setcc
1661 if (SCC.Val && SCC.getOpcode() == ISD::SETCC)
1662 return DAG.getBR2Way_CC(Chain, SCC.getOperand(2), SCC.getOperand(0),
1663 SCC.getOperand(1), N4, N5);
1667 SDOperand DAGCombiner::visitLOAD(SDNode *N) {
1668 SDOperand Chain = N->getOperand(0);
1669 SDOperand Ptr = N->getOperand(1);
1670 SDOperand SrcValue = N->getOperand(2);
1672 // If this load is directly stored, replace the load value with the stored
1674 // TODO: Handle store large -> read small portion.
1675 // TODO: Handle TRUNCSTORE/EXTLOAD
1676 if (Chain.getOpcode() == ISD::STORE && Chain.getOperand(2) == Ptr &&
1677 Chain.getOperand(1).getValueType() == N->getValueType(0))
1678 return CombineTo(N, Chain.getOperand(1), Chain);
1683 SDOperand DAGCombiner::visitSTORE(SDNode *N) {
1684 SDOperand Chain = N->getOperand(0);
1685 SDOperand Value = N->getOperand(1);
1686 SDOperand Ptr = N->getOperand(2);
1687 SDOperand SrcValue = N->getOperand(3);
1689 // If this is a store that kills a previous store, remove the previous store.
1690 if (Chain.getOpcode() == ISD::STORE && Chain.getOperand(2) == Ptr &&
1691 Chain.Val->hasOneUse() /* Avoid introducing DAG cycles */) {
1692 // Create a new store of Value that replaces both stores.
1693 SDNode *PrevStore = Chain.Val;
1694 if (PrevStore->getOperand(1) == Value) // Same value multiply stored.
1696 SDOperand NewStore = DAG.getNode(ISD::STORE, MVT::Other,
1697 PrevStore->getOperand(0), Value, Ptr,
1699 CombineTo(N, NewStore); // Nuke this store.
1700 CombineTo(PrevStore, NewStore); // Nuke the previous store.
1701 return SDOperand(N, 0);
1707 SDOperand DAGCombiner::SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2){
1708 assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!");
1710 SDOperand SCC = SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), N1, N2,
1711 cast<CondCodeSDNode>(N0.getOperand(2))->get());
1712 // If we got a simplified select_cc node back from SimplifySelectCC, then
1713 // break it down into a new SETCC node, and a new SELECT node, and then return
1714 // the SELECT node, since we were called with a SELECT node.
1716 // Check to see if we got a select_cc back (to turn into setcc/select).
1717 // Otherwise, just return whatever node we got back, like fabs.
1718 if (SCC.getOpcode() == ISD::SELECT_CC) {
1719 SDOperand SETCC = DAG.getNode(ISD::SETCC, N0.getValueType(),
1720 SCC.getOperand(0), SCC.getOperand(1),
1722 WorkList.push_back(SETCC.Val);
1723 return DAG.getNode(ISD::SELECT, SCC.getValueType(), SCC.getOperand(2),
1724 SCC.getOperand(3), SETCC);
1731 SDOperand DAGCombiner::SimplifySelectCC(SDOperand N0, SDOperand N1,
1732 SDOperand N2, SDOperand N3,
1735 MVT::ValueType VT = N2.getValueType();
1736 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
1737 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
1738 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.Val);
1739 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.Val);
1741 // Determine if the condition we're dealing with is constant
1742 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false);
1743 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val);
1745 // fold select_cc true, x, y -> x
1746 if (SCCC && SCCC->getValue())
1748 // fold select_cc false, x, y -> y
1749 if (SCCC && SCCC->getValue() == 0)
1752 // Check to see if we can simplify the select into an fabs node
1753 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) {
1754 // Allow either -0.0 or 0.0
1755 if (CFP->getValue() == 0.0) {
1756 // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs
1757 if ((CC == ISD::SETGE || CC == ISD::SETGT) &&
1758 N0 == N2 && N3.getOpcode() == ISD::FNEG &&
1759 N2 == N3.getOperand(0))
1760 return DAG.getNode(ISD::FABS, VT, N0);
1762 // select (setl[te] X, +/-0.0), fneg(X), X -> fabs
1763 if ((CC == ISD::SETLT || CC == ISD::SETLE) &&
1764 N0 == N3 && N2.getOpcode() == ISD::FNEG &&
1765 N2.getOperand(0) == N3)
1766 return DAG.getNode(ISD::FABS, VT, N3);
1770 // Check to see if we can perform the "gzip trick", transforming
1771 // select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A
1772 if (N1C && N1C->isNullValue() && N3C && N3C->isNullValue() &&
1773 MVT::isInteger(N0.getValueType()) &&
1774 MVT::isInteger(N2.getValueType()) && CC == ISD::SETLT) {
1775 MVT::ValueType XType = N0.getValueType();
1776 MVT::ValueType AType = N2.getValueType();
1777 if (XType >= AType) {
1778 // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a
1779 // single-bit constant.
1780 if (N2C && ((N2C->getValue() & (N2C->getValue()-1)) == 0)) {
1781 unsigned ShCtV = Log2_64(N2C->getValue());
1782 ShCtV = MVT::getSizeInBits(XType)-ShCtV-1;
1783 SDOperand ShCt = DAG.getConstant(ShCtV, TLI.getShiftAmountTy());
1784 SDOperand Shift = DAG.getNode(ISD::SRL, XType, N0, ShCt);
1785 WorkList.push_back(Shift.Val);
1786 if (XType > AType) {
1787 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift);
1788 WorkList.push_back(Shift.Val);
1790 return DAG.getNode(ISD::AND, AType, Shift, N2);
1792 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0,
1793 DAG.getConstant(MVT::getSizeInBits(XType)-1,
1794 TLI.getShiftAmountTy()));
1795 WorkList.push_back(Shift.Val);
1796 if (XType > AType) {
1797 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift);
1798 WorkList.push_back(Shift.Val);
1800 return DAG.getNode(ISD::AND, AType, Shift, N2);
1804 // fold select C, 16, 0 -> shl C, 4
1805 if (N2C && N3C && N3C->isNullValue() && isPowerOf2_64(N2C->getValue()) &&
1806 TLI.getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult) {
1807 // Get a SetCC of the condition
1808 // FIXME: Should probably make sure that setcc is legal if we ever have a
1809 // target where it isn't.
1810 SDOperand Temp, SCC = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC);
1811 WorkList.push_back(SCC.Val);
1812 // cast from setcc result type to select result type
1814 Temp = DAG.getZeroExtendInReg(SCC, N2.getValueType());
1816 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getValueType(), SCC);
1817 WorkList.push_back(Temp.Val);
1818 // shl setcc result by log2 n2c
1819 return DAG.getNode(ISD::SHL, N2.getValueType(), Temp,
1820 DAG.getConstant(Log2_64(N2C->getValue()),
1821 TLI.getShiftAmountTy()));
1824 // Check to see if this is the equivalent of setcc
1825 // FIXME: Turn all of these into setcc if setcc if setcc is legal
1826 // otherwise, go ahead with the folds.
1827 if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getValue() == 1ULL)) {
1828 MVT::ValueType XType = N0.getValueType();
1829 if (TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultTy())) {
1830 SDOperand Res = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC);
1831 if (Res.getValueType() != VT)
1832 Res = DAG.getNode(ISD::ZERO_EXTEND, VT, Res);
1836 // seteq X, 0 -> srl (ctlz X, log2(size(X)))
1837 if (N1C && N1C->isNullValue() && CC == ISD::SETEQ &&
1838 TLI.isOperationLegal(ISD::CTLZ, XType)) {
1839 SDOperand Ctlz = DAG.getNode(ISD::CTLZ, XType, N0);
1840 return DAG.getNode(ISD::SRL, XType, Ctlz,
1841 DAG.getConstant(Log2_32(MVT::getSizeInBits(XType)),
1842 TLI.getShiftAmountTy()));
1844 // setgt X, 0 -> srl (and (-X, ~X), size(X)-1)
1845 if (N1C && N1C->isNullValue() && CC == ISD::SETGT) {
1846 SDOperand NegN0 = DAG.getNode(ISD::SUB, XType, DAG.getConstant(0, XType),
1848 SDOperand NotN0 = DAG.getNode(ISD::XOR, XType, N0,
1849 DAG.getConstant(~0ULL, XType));
1850 return DAG.getNode(ISD::SRL, XType,
1851 DAG.getNode(ISD::AND, XType, NegN0, NotN0),
1852 DAG.getConstant(MVT::getSizeInBits(XType)-1,
1853 TLI.getShiftAmountTy()));
1855 // setgt X, -1 -> xor (srl (X, size(X)-1), 1)
1856 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) {
1857 SDOperand Sign = DAG.getNode(ISD::SRL, XType, N0,
1858 DAG.getConstant(MVT::getSizeInBits(XType)-1,
1859 TLI.getShiftAmountTy()));
1860 return DAG.getNode(ISD::XOR, XType, Sign, DAG.getConstant(1, XType));
1864 // Check to see if this is an integer abs. select_cc setl[te] X, 0, -X, X ->
1865 // Y = sra (X, size(X)-1); xor (add (X, Y), Y)
1866 if (N1C && N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE) &&
1867 N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1)) {
1868 if (ConstantSDNode *SubC = dyn_cast<ConstantSDNode>(N2.getOperand(0))) {
1869 MVT::ValueType XType = N0.getValueType();
1870 if (SubC->isNullValue() && MVT::isInteger(XType)) {
1871 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0,
1872 DAG.getConstant(MVT::getSizeInBits(XType)-1,
1873 TLI.getShiftAmountTy()));
1874 SDOperand Add = DAG.getNode(ISD::ADD, XType, N0, Shift);
1875 WorkList.push_back(Shift.Val);
1876 WorkList.push_back(Add.Val);
1877 return DAG.getNode(ISD::XOR, XType, Add, Shift);
1885 SDOperand DAGCombiner::SimplifySetCC(MVT::ValueType VT, SDOperand N0,
1886 SDOperand N1, ISD::CondCode Cond,
1887 bool foldBooleans) {
1888 // These setcc operations always fold.
1892 case ISD::SETFALSE2: return DAG.getConstant(0, VT);
1894 case ISD::SETTRUE2: return DAG.getConstant(1, VT);
1897 if (ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val)) {
1898 uint64_t C1 = N1C->getValue();
1899 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val)) {
1900 uint64_t C0 = N0C->getValue();
1902 // Sign extend the operands if required
1903 if (ISD::isSignedIntSetCC(Cond)) {
1904 C0 = N0C->getSignExtended();
1905 C1 = N1C->getSignExtended();
1909 default: assert(0 && "Unknown integer setcc!");
1910 case ISD::SETEQ: return DAG.getConstant(C0 == C1, VT);
1911 case ISD::SETNE: return DAG.getConstant(C0 != C1, VT);
1912 case ISD::SETULT: return DAG.getConstant(C0 < C1, VT);
1913 case ISD::SETUGT: return DAG.getConstant(C0 > C1, VT);
1914 case ISD::SETULE: return DAG.getConstant(C0 <= C1, VT);
1915 case ISD::SETUGE: return DAG.getConstant(C0 >= C1, VT);
1916 case ISD::SETLT: return DAG.getConstant((int64_t)C0 < (int64_t)C1, VT);
1917 case ISD::SETGT: return DAG.getConstant((int64_t)C0 > (int64_t)C1, VT);
1918 case ISD::SETLE: return DAG.getConstant((int64_t)C0 <= (int64_t)C1, VT);
1919 case ISD::SETGE: return DAG.getConstant((int64_t)C0 >= (int64_t)C1, VT);
1922 // If the LHS is a ZERO_EXTEND, perform the comparison on the input.
1923 if (N0.getOpcode() == ISD::ZERO_EXTEND) {
1924 unsigned InSize = MVT::getSizeInBits(N0.getOperand(0).getValueType());
1926 // If the comparison constant has bits in the upper part, the
1927 // zero-extended value could never match.
1928 if (C1 & (~0ULL << InSize)) {
1929 unsigned VSize = MVT::getSizeInBits(N0.getValueType());
1933 case ISD::SETEQ: return DAG.getConstant(0, VT);
1936 case ISD::SETNE: return DAG.getConstant(1, VT);
1939 // True if the sign bit of C1 is set.
1940 return DAG.getConstant((C1 & (1ULL << VSize)) != 0, VT);
1943 // True if the sign bit of C1 isn't set.
1944 return DAG.getConstant((C1 & (1ULL << VSize)) == 0, VT);
1950 // Otherwise, we can perform the comparison with the low bits.
1958 return DAG.getSetCC(VT, N0.getOperand(0),
1959 DAG.getConstant(C1, N0.getOperand(0).getValueType()),
1962 break; // todo, be more careful with signed comparisons
1964 } else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
1965 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
1966 MVT::ValueType ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT();
1967 unsigned ExtSrcTyBits = MVT::getSizeInBits(ExtSrcTy);
1968 MVT::ValueType ExtDstTy = N0.getValueType();
1969 unsigned ExtDstTyBits = MVT::getSizeInBits(ExtDstTy);
1971 // If the extended part has any inconsistent bits, it cannot ever
1972 // compare equal. In other words, they have to be all ones or all
1975 (~0ULL >> (64-ExtSrcTyBits)) & (~0ULL << (ExtDstTyBits-1));
1976 if ((C1 & ExtBits) != 0 && (C1 & ExtBits) != ExtBits)
1977 return DAG.getConstant(Cond == ISD::SETNE, VT);
1980 MVT::ValueType Op0Ty = N0.getOperand(0).getValueType();
1981 if (Op0Ty == ExtSrcTy) {
1982 ZextOp = N0.getOperand(0);
1984 int64_t Imm = ~0ULL >> (64-ExtSrcTyBits);
1985 ZextOp = DAG.getNode(ISD::AND, Op0Ty, N0.getOperand(0),
1986 DAG.getConstant(Imm, Op0Ty));
1988 WorkList.push_back(ZextOp.Val);
1989 // Otherwise, make this a use of a zext.
1990 return DAG.getSetCC(VT, ZextOp,
1991 DAG.getConstant(C1 & (~0ULL>>(64-ExtSrcTyBits)),
1996 uint64_t MinVal, MaxVal;
1997 unsigned OperandBitSize = MVT::getSizeInBits(N1C->getValueType(0));
1998 if (ISD::isSignedIntSetCC(Cond)) {
1999 MinVal = 1ULL << (OperandBitSize-1);
2000 if (OperandBitSize != 1) // Avoid X >> 64, which is undefined.
2001 MaxVal = ~0ULL >> (65-OperandBitSize);
2006 MaxVal = ~0ULL >> (64-OperandBitSize);
2009 // Canonicalize GE/LE comparisons to use GT/LT comparisons.
2010 if (Cond == ISD::SETGE || Cond == ISD::SETUGE) {
2011 if (C1 == MinVal) return DAG.getConstant(1, VT); // X >= MIN --> true
2012 --C1; // X >= C0 --> X > (C0-1)
2013 return DAG.getSetCC(VT, N0, DAG.getConstant(C1, N1.getValueType()),
2014 (Cond == ISD::SETGE) ? ISD::SETGT : ISD::SETUGT);
2017 if (Cond == ISD::SETLE || Cond == ISD::SETULE) {
2018 if (C1 == MaxVal) return DAG.getConstant(1, VT); // X <= MAX --> true
2019 ++C1; // X <= C0 --> X < (C0+1)
2020 return DAG.getSetCC(VT, N0, DAG.getConstant(C1, N1.getValueType()),
2021 (Cond == ISD::SETLE) ? ISD::SETLT : ISD::SETULT);
2024 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal)
2025 return DAG.getConstant(0, VT); // X < MIN --> false
2027 // Canonicalize setgt X, Min --> setne X, Min
2028 if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MinVal)
2029 return DAG.getSetCC(VT, N0, N1, ISD::SETNE);
2031 // If we have setult X, 1, turn it into seteq X, 0
2032 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal+1)
2033 return DAG.getSetCC(VT, N0, DAG.getConstant(MinVal, N0.getValueType()),
2035 // If we have setugt X, Max-1, turn it into seteq X, Max
2036 else if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal-1)
2037 return DAG.getSetCC(VT, N0, DAG.getConstant(MaxVal, N0.getValueType()),
2040 // If we have "setcc X, C0", check to see if we can shrink the immediate
2043 // SETUGT X, SINTMAX -> SETLT X, 0
2044 if (Cond == ISD::SETUGT && OperandBitSize != 1 &&
2045 C1 == (~0ULL >> (65-OperandBitSize)))
2046 return DAG.getSetCC(VT, N0, DAG.getConstant(0, N1.getValueType()),
2049 // FIXME: Implement the rest of these.
2051 // Fold bit comparisons when we can.
2052 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
2053 VT == N0.getValueType() && N0.getOpcode() == ISD::AND)
2054 if (ConstantSDNode *AndRHS =
2055 dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
2056 if (Cond == ISD::SETNE && C1 == 0) {// (X & 8) != 0 --> (X & 8) >> 3
2057 // Perform the xform if the AND RHS is a single bit.
2058 if ((AndRHS->getValue() & (AndRHS->getValue()-1)) == 0) {
2059 return DAG.getNode(ISD::SRL, VT, N0,
2060 DAG.getConstant(Log2_64(AndRHS->getValue()),
2061 TLI.getShiftAmountTy()));
2063 } else if (Cond == ISD::SETEQ && C1 == AndRHS->getValue()) {
2064 // (X & 8) == 8 --> (X & 8) >> 3
2065 // Perform the xform if C1 is a single bit.
2066 if ((C1 & (C1-1)) == 0) {
2067 return DAG.getNode(ISD::SRL, VT, N0,
2068 DAG.getConstant(Log2_64(C1),TLI.getShiftAmountTy()));
2073 } else if (isa<ConstantSDNode>(N0.Val)) {
2074 // Ensure that the constant occurs on the RHS.
2075 return DAG.getSetCC(VT, N1, N0, ISD::getSetCCSwappedOperands(Cond));
2078 if (ConstantFPSDNode *N0C = dyn_cast<ConstantFPSDNode>(N0.Val))
2079 if (ConstantFPSDNode *N1C = dyn_cast<ConstantFPSDNode>(N1.Val)) {
2080 double C0 = N0C->getValue(), C1 = N1C->getValue();
2083 default: break; // FIXME: Implement the rest of these!
2084 case ISD::SETEQ: return DAG.getConstant(C0 == C1, VT);
2085 case ISD::SETNE: return DAG.getConstant(C0 != C1, VT);
2086 case ISD::SETLT: return DAG.getConstant(C0 < C1, VT);
2087 case ISD::SETGT: return DAG.getConstant(C0 > C1, VT);
2088 case ISD::SETLE: return DAG.getConstant(C0 <= C1, VT);
2089 case ISD::SETGE: return DAG.getConstant(C0 >= C1, VT);
2092 // Ensure that the constant occurs on the RHS.
2093 return DAG.getSetCC(VT, N1, N0, ISD::getSetCCSwappedOperands(Cond));
2097 // We can always fold X == Y for integer setcc's.
2098 if (MVT::isInteger(N0.getValueType()))
2099 return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
2100 unsigned UOF = ISD::getUnorderedFlavor(Cond);
2101 if (UOF == 2) // FP operators that are undefined on NaNs.
2102 return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
2103 if (UOF == unsigned(ISD::isTrueWhenEqual(Cond)))
2104 return DAG.getConstant(UOF, VT);
2105 // Otherwise, we can't fold it. However, we can simplify it to SETUO/SETO
2106 // if it is not already.
2107 ISD::CondCode NewCond = UOF == 0 ? ISD::SETUO : ISD::SETO;
2108 if (NewCond != Cond)
2109 return DAG.getSetCC(VT, N0, N1, NewCond);
2112 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
2113 MVT::isInteger(N0.getValueType())) {
2114 if (N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::SUB ||
2115 N0.getOpcode() == ISD::XOR) {
2116 // Simplify (X+Y) == (X+Z) --> Y == Z
2117 if (N0.getOpcode() == N1.getOpcode()) {
2118 if (N0.getOperand(0) == N1.getOperand(0))
2119 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(1), Cond);
2120 if (N0.getOperand(1) == N1.getOperand(1))
2121 return DAG.getSetCC(VT, N0.getOperand(0), N1.getOperand(0), Cond);
2122 if (isCommutativeBinOp(N0.getOpcode())) {
2123 // If X op Y == Y op X, try other combinations.
2124 if (N0.getOperand(0) == N1.getOperand(1))
2125 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(0), Cond);
2126 if (N0.getOperand(1) == N1.getOperand(0))
2127 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(1), Cond);
2131 // Turn (X^C1) == C2 into X == C1^C2 iff X&~C1 = 0. Common for condcodes.
2132 if (N0.getOpcode() == ISD::XOR)
2133 if (ConstantSDNode *XORC = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
2134 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(N1)) {
2135 // If we know that all of the inverted bits are zero, don't bother
2136 // performing the inversion.
2137 if (MaskedValueIsZero(N0.getOperand(0), ~XORC->getValue(), TLI))
2138 return DAG.getSetCC(VT, N0.getOperand(0),
2139 DAG.getConstant(XORC->getValue()^RHSC->getValue(),
2140 N0.getValueType()), Cond);
2143 // Simplify (X+Z) == X --> Z == 0
2144 if (N0.getOperand(0) == N1)
2145 return DAG.getSetCC(VT, N0.getOperand(1),
2146 DAG.getConstant(0, N0.getValueType()), Cond);
2147 if (N0.getOperand(1) == N1) {
2148 if (isCommutativeBinOp(N0.getOpcode()))
2149 return DAG.getSetCC(VT, N0.getOperand(0),
2150 DAG.getConstant(0, N0.getValueType()), Cond);
2152 assert(N0.getOpcode() == ISD::SUB && "Unexpected operation!");
2153 // (Z-X) == X --> Z == X<<1
2154 SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(),
2156 DAG.getConstant(1,TLI.getShiftAmountTy()));
2157 WorkList.push_back(SH.Val);
2158 return DAG.getSetCC(VT, N0.getOperand(0), SH, Cond);
2163 if (N1.getOpcode() == ISD::ADD || N1.getOpcode() == ISD::SUB ||
2164 N1.getOpcode() == ISD::XOR) {
2165 // Simplify X == (X+Z) --> Z == 0
2166 if (N1.getOperand(0) == N0) {
2167 return DAG.getSetCC(VT, N1.getOperand(1),
2168 DAG.getConstant(0, N1.getValueType()), Cond);
2169 } else if (N1.getOperand(1) == N0) {
2170 if (isCommutativeBinOp(N1.getOpcode())) {
2171 return DAG.getSetCC(VT, N1.getOperand(0),
2172 DAG.getConstant(0, N1.getValueType()), Cond);
2174 assert(N1.getOpcode() == ISD::SUB && "Unexpected operation!");
2175 // X == (Z-X) --> X<<1 == Z
2176 SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(), N0,
2177 DAG.getConstant(1,TLI.getShiftAmountTy()));
2178 WorkList.push_back(SH.Val);
2179 return DAG.getSetCC(VT, SH, N1.getOperand(0), Cond);
2185 // Fold away ALL boolean setcc's.
2187 if (N0.getValueType() == MVT::i1 && foldBooleans) {
2189 default: assert(0 && "Unknown integer setcc!");
2190 case ISD::SETEQ: // X == Y -> (X^Y)^1
2191 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, N1);
2192 N0 = DAG.getNode(ISD::XOR, MVT::i1, Temp, DAG.getConstant(1, MVT::i1));
2193 WorkList.push_back(Temp.Val);
2195 case ISD::SETNE: // X != Y --> (X^Y)
2196 N0 = DAG.getNode(ISD::XOR, MVT::i1, N0, N1);
2198 case ISD::SETGT: // X >s Y --> X == 0 & Y == 1 --> X^1 & Y
2199 case ISD::SETULT: // X <u Y --> X == 0 & Y == 1 --> X^1 & Y
2200 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1));
2201 N0 = DAG.getNode(ISD::AND, MVT::i1, N1, Temp);
2202 WorkList.push_back(Temp.Val);
2204 case ISD::SETLT: // X <s Y --> X == 1 & Y == 0 --> Y^1 & X
2205 case ISD::SETUGT: // X >u Y --> X == 1 & Y == 0 --> Y^1 & X
2206 Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1));
2207 N0 = DAG.getNode(ISD::AND, MVT::i1, N0, Temp);
2208 WorkList.push_back(Temp.Val);
2210 case ISD::SETULE: // X <=u Y --> X == 0 | Y == 1 --> X^1 | Y
2211 case ISD::SETGE: // X >=s Y --> X == 0 | Y == 1 --> X^1 | Y
2212 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1));
2213 N0 = DAG.getNode(ISD::OR, MVT::i1, N1, Temp);
2214 WorkList.push_back(Temp.Val);
2216 case ISD::SETUGE: // X >=u Y --> X == 1 | Y == 0 --> Y^1 | X
2217 case ISD::SETLE: // X <=s Y --> X == 1 | Y == 0 --> Y^1 | X
2218 Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1));
2219 N0 = DAG.getNode(ISD::OR, MVT::i1, N0, Temp);
2222 if (VT != MVT::i1) {
2223 WorkList.push_back(N0.Val);
2224 // FIXME: If running after legalize, we probably can't do this.
2225 N0 = DAG.getNode(ISD::ZERO_EXTEND, VT, N0);
2230 // Could not fold it.
2234 // SelectionDAG::Combine - This is the entry point for the file.
2236 void SelectionDAG::Combine(bool RunningAfterLegalize) {
2237 /// run - This is the main entry point to this class.
2239 DAGCombiner(*this).Run(RunningAfterLegalize);