1 //===- X86InstrInfo.cpp - X86 Instruction Information -----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains the X86 implementation of the TargetInstrInfo class.
12 //===----------------------------------------------------------------------===//
14 #include "X86InstrInfo.h"
16 #include "X86GenInstrInfo.inc"
17 #include "X86InstrBuilder.h"
18 #include "X86Subtarget.h"
19 #include "X86TargetMachine.h"
20 #include "llvm/ADT/STLExtras.h"
21 #include "llvm/CodeGen/MachineInstrBuilder.h"
22 #include "llvm/CodeGen/LiveVariables.h"
23 #include "llvm/CodeGen/SSARegMap.h"
24 #include "llvm/Target/TargetOptions.h"
25 #include "llvm/Support/CommandLine.h"
30 EnableCommuteCMove("enable-x86-commute-cmove",
31 cl::desc("Commute conditional moves by inverting conditions"));
34 X86InstrInfo::X86InstrInfo(X86TargetMachine &tm)
35 : TargetInstrInfo(X86Insts, array_lengthof(X86Insts)),
36 TM(tm), RI(tm, *this) {
39 bool X86InstrInfo::isMoveInstr(const MachineInstr& MI,
41 unsigned& destReg) const {
42 MachineOpCode oc = MI.getOpcode();
43 if (oc == X86::MOV8rr || oc == X86::MOV16rr ||
44 oc == X86::MOV32rr || oc == X86::MOV64rr ||
45 oc == X86::MOV16to16_ || oc == X86::MOV32to32_ ||
46 oc == X86::MOV_Fp3232 || oc == X86::MOVSSrr || oc == X86::MOVSDrr ||
47 oc == X86::MOV_Fp3264 || oc == X86::MOV_Fp6432 || oc == X86::MOV_Fp6464 ||
48 oc == X86::FsMOVAPSrr || oc == X86::FsMOVAPDrr ||
49 oc == X86::MOVAPSrr || oc == X86::MOVAPDrr ||
50 oc == X86::MOVSS2PSrr || oc == X86::MOVSD2PDrr ||
51 oc == X86::MOVPS2SSrr || oc == X86::MOVPD2SDrr ||
52 oc == X86::MMX_MOVD64rr || oc == X86::MMX_MOVQ64rr) {
53 assert(MI.getNumOperands() >= 2 &&
54 MI.getOperand(0).isRegister() &&
55 MI.getOperand(1).isRegister() &&
56 "invalid register-register move instruction");
57 sourceReg = MI.getOperand(1).getReg();
58 destReg = MI.getOperand(0).getReg();
64 unsigned X86InstrInfo::isLoadFromStackSlot(MachineInstr *MI,
65 int &FrameIndex) const {
66 switch (MI->getOpcode()) {
79 case X86::MMX_MOVD64rm:
80 case X86::MMX_MOVQ64rm:
81 if (MI->getOperand(1).isFrameIndex() && MI->getOperand(2).isImmediate() &&
82 MI->getOperand(3).isRegister() && MI->getOperand(4).isImmediate() &&
83 MI->getOperand(2).getImmedValue() == 1 &&
84 MI->getOperand(3).getReg() == 0 &&
85 MI->getOperand(4).getImmedValue() == 0) {
86 FrameIndex = MI->getOperand(1).getFrameIndex();
87 return MI->getOperand(0).getReg();
94 unsigned X86InstrInfo::isStoreToStackSlot(MachineInstr *MI,
95 int &FrameIndex) const {
96 switch (MI->getOpcode()) {
109 case X86::MMX_MOVD64mr:
110 case X86::MMX_MOVQ64mr:
111 case X86::MMX_MOVNTQmr:
112 if (MI->getOperand(0).isFrameIndex() && MI->getOperand(1).isImmediate() &&
113 MI->getOperand(2).isRegister() && MI->getOperand(3).isImmediate() &&
114 MI->getOperand(1).getImmedValue() == 1 &&
115 MI->getOperand(2).getReg() == 0 &&
116 MI->getOperand(3).getImmedValue() == 0) {
117 FrameIndex = MI->getOperand(0).getFrameIndex();
118 return MI->getOperand(4).getReg();
126 bool X86InstrInfo::isReallyTriviallyReMaterializable(MachineInstr *MI) const {
127 switch (MI->getOpcode()) {
140 case X86::MMX_MOVD64rm:
141 case X86::MMX_MOVQ64rm:
142 // Loads from constant pools are trivially rematerializable.
143 return MI->getOperand(1).isRegister() && MI->getOperand(2).isImmediate() &&
144 MI->getOperand(3).isRegister() && MI->getOperand(4).isConstantPoolIndex() &&
145 MI->getOperand(1).getReg() == 0 &&
146 MI->getOperand(2).getImmedValue() == 1 &&
147 MI->getOperand(3).getReg() == 0;
149 // All other instructions marked M_REMATERIALIZABLE are always trivially
154 /// hasLiveCondCodeDef - True if MI has a condition code def, e.g. EFLAGS, that
155 /// is not marked dead.
156 static bool hasLiveCondCodeDef(MachineInstr *MI) {
157 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
158 MachineOperand &MO = MI->getOperand(i);
159 if (MO.isRegister() && MO.isDef() &&
160 MO.getReg() == X86::EFLAGS && !MO.isDead()) {
167 /// convertToThreeAddress - This method must be implemented by targets that
168 /// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
169 /// may be able to convert a two-address instruction into a true
170 /// three-address instruction on demand. This allows the X86 target (for
171 /// example) to convert ADD and SHL instructions into LEA instructions if they
172 /// would require register copies due to two-addressness.
174 /// This method returns a null pointer if the transformation cannot be
175 /// performed, otherwise it returns the new instruction.
178 X86InstrInfo::convertToThreeAddress(MachineFunction::iterator &MFI,
179 MachineBasicBlock::iterator &MBBI,
180 LiveVariables &LV) const {
181 MachineInstr *MI = MBBI;
182 // All instructions input are two-addr instructions. Get the known operands.
183 unsigned Dest = MI->getOperand(0).getReg();
184 unsigned Src = MI->getOperand(1).getReg();
186 MachineInstr *NewMI = NULL;
187 // FIXME: 16-bit LEA's are really slow on Athlons, but not bad on P4's. When
188 // we have better subtarget support, enable the 16-bit LEA generation here.
189 bool DisableLEA16 = true;
191 unsigned MIOpc = MI->getOpcode();
193 case X86::SHUFPSrri: {
194 assert(MI->getNumOperands() == 4 && "Unknown shufps instruction!");
195 if (!TM.getSubtarget<X86Subtarget>().hasSSE2()) return 0;
197 unsigned A = MI->getOperand(0).getReg();
198 unsigned B = MI->getOperand(1).getReg();
199 unsigned C = MI->getOperand(2).getReg();
200 unsigned M = MI->getOperand(3).getImm();
201 if (B != C) return 0;
202 NewMI = BuildMI(get(X86::PSHUFDri), A).addReg(B).addImm(M);
206 assert(MI->getNumOperands() >= 3 && "Unknown shift instruction!");
207 // NOTE: LEA doesn't produce flags like shift does, but LLVM never uses
208 // the flags produced by a shift yet, so this is safe.
209 unsigned Dest = MI->getOperand(0).getReg();
210 unsigned Src = MI->getOperand(1).getReg();
211 unsigned ShAmt = MI->getOperand(2).getImm();
212 if (ShAmt == 0 || ShAmt >= 4) return 0;
214 NewMI = BuildMI(get(X86::LEA64r), Dest)
215 .addReg(0).addImm(1 << ShAmt).addReg(Src).addImm(0);
219 assert(MI->getNumOperands() >= 3 && "Unknown shift instruction!");
220 // NOTE: LEA doesn't produce flags like shift does, but LLVM never uses
221 // the flags produced by a shift yet, so this is safe.
222 unsigned Dest = MI->getOperand(0).getReg();
223 unsigned Src = MI->getOperand(1).getReg();
224 unsigned ShAmt = MI->getOperand(2).getImm();
225 if (ShAmt == 0 || ShAmt >= 4) return 0;
227 unsigned Opc = TM.getSubtarget<X86Subtarget>().is64Bit() ?
228 X86::LEA64_32r : X86::LEA32r;
229 NewMI = BuildMI(get(Opc), Dest)
230 .addReg(0).addImm(1 << ShAmt).addReg(Src).addImm(0);
234 assert(MI->getNumOperands() >= 3 && "Unknown shift instruction!");
235 // NOTE: LEA doesn't produce flags like shift does, but LLVM never uses
236 // the flags produced by a shift yet, so this is safe.
237 unsigned Dest = MI->getOperand(0).getReg();
238 unsigned Src = MI->getOperand(1).getReg();
239 unsigned ShAmt = MI->getOperand(2).getImm();
240 if (ShAmt == 0 || ShAmt >= 4) return 0;
243 // If 16-bit LEA is disabled, use 32-bit LEA via subregisters.
244 SSARegMap *RegMap = MFI->getParent()->getSSARegMap();
245 unsigned Opc = TM.getSubtarget<X86Subtarget>().is64Bit()
246 ? X86::LEA64_32r : X86::LEA32r;
247 unsigned leaInReg = RegMap->createVirtualRegister(&X86::GR32RegClass);
248 unsigned leaOutReg = RegMap->createVirtualRegister(&X86::GR32RegClass);
251 BuildMI(get(X86::INSERT_SUBREG), leaInReg).addReg(Src).addImm(2);
252 Ins->copyKillDeadInfo(MI);
254 NewMI = BuildMI(get(Opc), leaOutReg)
255 .addReg(0).addImm(1 << ShAmt).addReg(leaInReg).addImm(0);
258 BuildMI(get(X86::EXTRACT_SUBREG), Dest).addReg(leaOutReg).addImm(2);
259 Ext->copyKillDeadInfo(MI);
261 MFI->insert(MBBI, Ins); // Insert the insert_subreg
262 LV.instructionChanged(MI, NewMI); // Update live variables
263 LV.addVirtualRegisterKilled(leaInReg, NewMI);
264 MFI->insert(MBBI, NewMI); // Insert the new inst
265 LV.addVirtualRegisterKilled(leaOutReg, Ext);
266 MFI->insert(MBBI, Ext); // Insert the extract_subreg
269 NewMI = BuildMI(get(X86::LEA16r), Dest)
270 .addReg(0).addImm(1 << ShAmt).addReg(Src).addImm(0);
275 // The following opcodes also sets the condition code register(s). Only
276 // convert them to equivalent lea if the condition code register def's
278 if (hasLiveCondCodeDef(MI))
285 assert(MI->getNumOperands() >= 2 && "Unknown inc instruction!");
286 unsigned Opc = MIOpc == X86::INC64r ? X86::LEA64r : X86::LEA32r;
287 NewMI = addRegOffset(BuildMI(get(Opc), Dest), Src, 1);
292 if (DisableLEA16) return 0;
293 assert(MI->getNumOperands() >= 2 && "Unknown inc instruction!");
294 NewMI = addRegOffset(BuildMI(get(X86::LEA16r), Dest), Src, 1);
298 assert(MI->getNumOperands() >= 2 && "Unknown dec instruction!");
299 unsigned Opc = MIOpc == X86::DEC64r ? X86::LEA64r : X86::LEA32r;
300 NewMI = addRegOffset(BuildMI(get(Opc), Dest), Src, -1);
305 if (DisableLEA16) return 0;
306 assert(MI->getNumOperands() >= 2 && "Unknown dec instruction!");
307 NewMI = addRegOffset(BuildMI(get(X86::LEA16r), Dest), Src, -1);
311 assert(MI->getNumOperands() >= 3 && "Unknown add instruction!");
312 unsigned Opc = MIOpc == X86::ADD64rr ? X86::LEA64r : X86::LEA32r;
313 NewMI = addRegReg(BuildMI(get(Opc), Dest), Src,
314 MI->getOperand(2).getReg());
318 if (DisableLEA16) return 0;
319 assert(MI->getNumOperands() >= 3 && "Unknown add instruction!");
320 NewMI = addRegReg(BuildMI(get(X86::LEA16r), Dest), Src,
321 MI->getOperand(2).getReg());
325 assert(MI->getNumOperands() >= 3 && "Unknown add instruction!");
326 if (MI->getOperand(2).isImmediate())
327 NewMI = addRegOffset(BuildMI(get(X86::LEA64r), Dest), Src,
328 MI->getOperand(2).getImmedValue());
332 assert(MI->getNumOperands() >= 3 && "Unknown add instruction!");
333 if (MI->getOperand(2).isImmediate())
334 NewMI = addRegOffset(BuildMI(get(X86::LEA32r), Dest), Src,
335 MI->getOperand(2).getImmedValue());
339 if (DisableLEA16) return 0;
340 assert(MI->getNumOperands() >= 3 && "Unknown add instruction!");
341 if (MI->getOperand(2).isImmediate())
342 NewMI = addRegOffset(BuildMI(get(X86::LEA16r), Dest), Src,
343 MI->getOperand(2).getImmedValue());
346 if (DisableLEA16) return 0;
349 assert(MI->getNumOperands() >= 3 && MI->getOperand(2).isImmediate() &&
350 "Unknown shl instruction!");
351 unsigned ShAmt = MI->getOperand(2).getImmedValue();
352 if (ShAmt == 1 || ShAmt == 2 || ShAmt == 3) {
354 AM.Scale = 1 << ShAmt;
356 unsigned Opc = MIOpc == X86::SHL64ri ? X86::LEA64r
357 : (MIOpc == X86::SHL32ri ? X86::LEA32r : X86::LEA16r);
358 NewMI = addFullAddress(BuildMI(get(Opc), Dest), AM);
366 NewMI->copyKillDeadInfo(MI);
367 LV.instructionChanged(MI, NewMI); // Update live variables
368 MFI->insert(MBBI, NewMI); // Insert the new inst
372 /// commuteInstruction - We have a few instructions that must be hacked on to
375 MachineInstr *X86InstrInfo::commuteInstruction(MachineInstr *MI) const {
376 switch (MI->getOpcode()) {
377 case X86::SHRD16rri8: // A = SHRD16rri8 B, C, I -> A = SHLD16rri8 C, B, (16-I)
378 case X86::SHLD16rri8: // A = SHLD16rri8 B, C, I -> A = SHRD16rri8 C, B, (16-I)
379 case X86::SHRD32rri8: // A = SHRD32rri8 B, C, I -> A = SHLD32rri8 C, B, (32-I)
380 case X86::SHLD32rri8: // A = SHLD32rri8 B, C, I -> A = SHRD32rri8 C, B, (32-I)
381 case X86::SHRD64rri8: // A = SHRD64rri8 B, C, I -> A = SHLD64rri8 C, B, (64-I)
382 case X86::SHLD64rri8:{// A = SHLD64rri8 B, C, I -> A = SHRD64rri8 C, B, (64-I)
385 switch (MI->getOpcode()) {
386 default: assert(0 && "Unreachable!");
387 case X86::SHRD16rri8: Size = 16; Opc = X86::SHLD16rri8; break;
388 case X86::SHLD16rri8: Size = 16; Opc = X86::SHRD16rri8; break;
389 case X86::SHRD32rri8: Size = 32; Opc = X86::SHLD32rri8; break;
390 case X86::SHLD32rri8: Size = 32; Opc = X86::SHRD32rri8; break;
391 case X86::SHRD64rri8: Size = 64; Opc = X86::SHLD64rri8; break;
392 case X86::SHLD64rri8: Size = 64; Opc = X86::SHRD64rri8; break;
394 unsigned Amt = MI->getOperand(3).getImmedValue();
395 unsigned A = MI->getOperand(0).getReg();
396 unsigned B = MI->getOperand(1).getReg();
397 unsigned C = MI->getOperand(2).getReg();
398 bool BisKill = MI->getOperand(1).isKill();
399 bool CisKill = MI->getOperand(2).isKill();
400 return BuildMI(get(Opc), A).addReg(C, false, false, CisKill)
401 .addReg(B, false, false, BisKill).addImm(Size-Amt);
406 case X86::CMOVAE16rr:
407 case X86::CMOVAE32rr:
408 case X86::CMOVAE64rr:
412 case X86::CMOVNE16rr:
413 case X86::CMOVNE32rr:
414 case X86::CMOVNE64rr:
415 case X86::CMOVBE16rr:
416 case X86::CMOVBE32rr:
417 case X86::CMOVBE64rr:
424 case X86::CMOVGE16rr:
425 case X86::CMOVGE32rr:
426 case X86::CMOVGE64rr:
427 case X86::CMOVLE16rr:
428 case X86::CMOVLE32rr:
429 case X86::CMOVLE64rr:
436 case X86::CMOVNS16rr:
437 case X86::CMOVNS32rr:
438 case X86::CMOVNS64rr:
442 case X86::CMOVNP16rr:
443 case X86::CMOVNP32rr:
444 case X86::CMOVNP64rr: {
445 if (!EnableCommuteCMove)
448 switch (MI->getOpcode()) {
450 case X86::CMOVB16rr: Opc = X86::CMOVAE16rr; break;
451 case X86::CMOVB32rr: Opc = X86::CMOVAE32rr; break;
452 case X86::CMOVB64rr: Opc = X86::CMOVAE64rr; break;
453 case X86::CMOVAE16rr: Opc = X86::CMOVB16rr; break;
454 case X86::CMOVAE32rr: Opc = X86::CMOVB32rr; break;
455 case X86::CMOVAE64rr: Opc = X86::CMOVB64rr; break;
456 case X86::CMOVE16rr: Opc = X86::CMOVNE16rr; break;
457 case X86::CMOVE32rr: Opc = X86::CMOVNE32rr; break;
458 case X86::CMOVE64rr: Opc = X86::CMOVNE64rr; break;
459 case X86::CMOVNE16rr: Opc = X86::CMOVE16rr; break;
460 case X86::CMOVNE32rr: Opc = X86::CMOVE32rr; break;
461 case X86::CMOVNE64rr: Opc = X86::CMOVE64rr; break;
462 case X86::CMOVBE16rr: Opc = X86::CMOVA16rr; break;
463 case X86::CMOVBE32rr: Opc = X86::CMOVA32rr; break;
464 case X86::CMOVBE64rr: Opc = X86::CMOVA64rr; break;
465 case X86::CMOVA16rr: Opc = X86::CMOVBE16rr; break;
466 case X86::CMOVA32rr: Opc = X86::CMOVBE32rr; break;
467 case X86::CMOVA64rr: Opc = X86::CMOVBE64rr; break;
468 case X86::CMOVL16rr: Opc = X86::CMOVGE16rr; break;
469 case X86::CMOVL32rr: Opc = X86::CMOVGE32rr; break;
470 case X86::CMOVL64rr: Opc = X86::CMOVGE64rr; break;
471 case X86::CMOVGE16rr: Opc = X86::CMOVL16rr; break;
472 case X86::CMOVGE32rr: Opc = X86::CMOVL32rr; break;
473 case X86::CMOVGE64rr: Opc = X86::CMOVL64rr; break;
474 case X86::CMOVLE16rr: Opc = X86::CMOVG16rr; break;
475 case X86::CMOVLE32rr: Opc = X86::CMOVG32rr; break;
476 case X86::CMOVLE64rr: Opc = X86::CMOVG64rr; break;
477 case X86::CMOVG16rr: Opc = X86::CMOVLE16rr; break;
478 case X86::CMOVG32rr: Opc = X86::CMOVLE32rr; break;
479 case X86::CMOVG64rr: Opc = X86::CMOVLE64rr; break;
480 case X86::CMOVS16rr: Opc = X86::CMOVNS16rr; break;
481 case X86::CMOVS32rr: Opc = X86::CMOVNS32rr; break;
482 case X86::CMOVS64rr: Opc = X86::CMOVNS32rr; break;
483 case X86::CMOVNS16rr: Opc = X86::CMOVS16rr; break;
484 case X86::CMOVNS32rr: Opc = X86::CMOVS32rr; break;
485 case X86::CMOVNS64rr: Opc = X86::CMOVS64rr; break;
486 case X86::CMOVP16rr: Opc = X86::CMOVNP16rr; break;
487 case X86::CMOVP32rr: Opc = X86::CMOVNP32rr; break;
488 case X86::CMOVP64rr: Opc = X86::CMOVNP32rr; break;
489 case X86::CMOVNP16rr: Opc = X86::CMOVP16rr; break;
490 case X86::CMOVNP32rr: Opc = X86::CMOVP32rr; break;
491 case X86::CMOVNP64rr: Opc = X86::CMOVP64rr; break;
494 MI->setInstrDescriptor(get(Opc));
495 // Fallthrough intended.
498 return TargetInstrInfo::commuteInstruction(MI);
502 static X86::CondCode GetCondFromBranchOpc(unsigned BrOpc) {
504 default: return X86::COND_INVALID;
505 case X86::JE: return X86::COND_E;
506 case X86::JNE: return X86::COND_NE;
507 case X86::JL: return X86::COND_L;
508 case X86::JLE: return X86::COND_LE;
509 case X86::JG: return X86::COND_G;
510 case X86::JGE: return X86::COND_GE;
511 case X86::JB: return X86::COND_B;
512 case X86::JBE: return X86::COND_BE;
513 case X86::JA: return X86::COND_A;
514 case X86::JAE: return X86::COND_AE;
515 case X86::JS: return X86::COND_S;
516 case X86::JNS: return X86::COND_NS;
517 case X86::JP: return X86::COND_P;
518 case X86::JNP: return X86::COND_NP;
519 case X86::JO: return X86::COND_O;
520 case X86::JNO: return X86::COND_NO;
524 unsigned X86::GetCondBranchFromCond(X86::CondCode CC) {
526 default: assert(0 && "Illegal condition code!");
527 case X86::COND_E: return X86::JE;
528 case X86::COND_NE: return X86::JNE;
529 case X86::COND_L: return X86::JL;
530 case X86::COND_LE: return X86::JLE;
531 case X86::COND_G: return X86::JG;
532 case X86::COND_GE: return X86::JGE;
533 case X86::COND_B: return X86::JB;
534 case X86::COND_BE: return X86::JBE;
535 case X86::COND_A: return X86::JA;
536 case X86::COND_AE: return X86::JAE;
537 case X86::COND_S: return X86::JS;
538 case X86::COND_NS: return X86::JNS;
539 case X86::COND_P: return X86::JP;
540 case X86::COND_NP: return X86::JNP;
541 case X86::COND_O: return X86::JO;
542 case X86::COND_NO: return X86::JNO;
546 /// GetOppositeBranchCondition - Return the inverse of the specified condition,
547 /// e.g. turning COND_E to COND_NE.
548 X86::CondCode X86::GetOppositeBranchCondition(X86::CondCode CC) {
550 default: assert(0 && "Illegal condition code!");
551 case X86::COND_E: return X86::COND_NE;
552 case X86::COND_NE: return X86::COND_E;
553 case X86::COND_L: return X86::COND_GE;
554 case X86::COND_LE: return X86::COND_G;
555 case X86::COND_G: return X86::COND_LE;
556 case X86::COND_GE: return X86::COND_L;
557 case X86::COND_B: return X86::COND_AE;
558 case X86::COND_BE: return X86::COND_A;
559 case X86::COND_A: return X86::COND_BE;
560 case X86::COND_AE: return X86::COND_B;
561 case X86::COND_S: return X86::COND_NS;
562 case X86::COND_NS: return X86::COND_S;
563 case X86::COND_P: return X86::COND_NP;
564 case X86::COND_NP: return X86::COND_P;
565 case X86::COND_O: return X86::COND_NO;
566 case X86::COND_NO: return X86::COND_O;
570 bool X86InstrInfo::isUnpredicatedTerminator(const MachineInstr *MI) const {
571 const TargetInstrDescriptor *TID = MI->getInstrDescriptor();
572 if (TID->Flags & M_TERMINATOR_FLAG) {
573 // Conditional branch is a special case.
574 if ((TID->Flags & M_BRANCH_FLAG) != 0 && (TID->Flags & M_BARRIER_FLAG) == 0)
576 if ((TID->Flags & M_PREDICABLE) == 0)
578 return !isPredicated(MI);
583 // For purposes of branch analysis do not count FP_REG_KILL as a terminator.
584 static bool isBrAnalysisUnpredicatedTerminator(const MachineInstr *MI,
585 const X86InstrInfo &TII) {
586 if (MI->getOpcode() == X86::FP_REG_KILL)
588 return TII.isUnpredicatedTerminator(MI);
591 bool X86InstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,
592 MachineBasicBlock *&TBB,
593 MachineBasicBlock *&FBB,
594 std::vector<MachineOperand> &Cond) const {
595 // If the block has no terminators, it just falls into the block after it.
596 MachineBasicBlock::iterator I = MBB.end();
597 if (I == MBB.begin() || !isBrAnalysisUnpredicatedTerminator(--I, *this))
600 // Get the last instruction in the block.
601 MachineInstr *LastInst = I;
603 // If there is only one terminator instruction, process it.
604 if (I == MBB.begin() || !isBrAnalysisUnpredicatedTerminator(--I, *this)) {
605 if (!isBranch(LastInst->getOpcode()))
608 // If the block ends with a branch there are 3 possibilities:
609 // it's an unconditional, conditional, or indirect branch.
611 if (LastInst->getOpcode() == X86::JMP) {
612 TBB = LastInst->getOperand(0).getMachineBasicBlock();
615 X86::CondCode BranchCode = GetCondFromBranchOpc(LastInst->getOpcode());
616 if (BranchCode == X86::COND_INVALID)
617 return true; // Can't handle indirect branch.
619 // Otherwise, block ends with fall-through condbranch.
620 TBB = LastInst->getOperand(0).getMachineBasicBlock();
621 Cond.push_back(MachineOperand::CreateImm(BranchCode));
625 // Get the instruction before it if it's a terminator.
626 MachineInstr *SecondLastInst = I;
628 // If there are three terminators, we don't know what sort of block this is.
629 if (SecondLastInst && I != MBB.begin() &&
630 isBrAnalysisUnpredicatedTerminator(--I, *this))
633 // If the block ends with X86::JMP and a conditional branch, handle it.
634 X86::CondCode BranchCode = GetCondFromBranchOpc(SecondLastInst->getOpcode());
635 if (BranchCode != X86::COND_INVALID && LastInst->getOpcode() == X86::JMP) {
636 TBB = SecondLastInst->getOperand(0).getMachineBasicBlock();
637 Cond.push_back(MachineOperand::CreateImm(BranchCode));
638 FBB = LastInst->getOperand(0).getMachineBasicBlock();
642 // If the block ends with two X86::JMPs, handle it. The second one is not
643 // executed, so remove it.
644 if (SecondLastInst->getOpcode() == X86::JMP &&
645 LastInst->getOpcode() == X86::JMP) {
646 TBB = SecondLastInst->getOperand(0).getMachineBasicBlock();
648 I->eraseFromParent();
652 // Otherwise, can't handle this.
656 unsigned X86InstrInfo::RemoveBranch(MachineBasicBlock &MBB) const {
657 MachineBasicBlock::iterator I = MBB.end();
658 if (I == MBB.begin()) return 0;
660 if (I->getOpcode() != X86::JMP &&
661 GetCondFromBranchOpc(I->getOpcode()) == X86::COND_INVALID)
664 // Remove the branch.
665 I->eraseFromParent();
669 if (I == MBB.begin()) return 1;
671 if (GetCondFromBranchOpc(I->getOpcode()) == X86::COND_INVALID)
674 // Remove the branch.
675 I->eraseFromParent();
680 X86InstrInfo::InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
681 MachineBasicBlock *FBB,
682 const std::vector<MachineOperand> &Cond) const {
683 // Shouldn't be a fall through.
684 assert(TBB && "InsertBranch must not be told to insert a fallthrough");
685 assert((Cond.size() == 1 || Cond.size() == 0) &&
686 "X86 branch conditions have one component!");
688 if (FBB == 0) { // One way branch.
690 // Unconditional branch?
691 BuildMI(&MBB, get(X86::JMP)).addMBB(TBB);
693 // Conditional branch.
694 unsigned Opc = GetCondBranchFromCond((X86::CondCode)Cond[0].getImm());
695 BuildMI(&MBB, get(Opc)).addMBB(TBB);
700 // Two-way Conditional branch.
701 unsigned Opc = GetCondBranchFromCond((X86::CondCode)Cond[0].getImm());
702 BuildMI(&MBB, get(Opc)).addMBB(TBB);
703 BuildMI(&MBB, get(X86::JMP)).addMBB(FBB);
707 bool X86InstrInfo::BlockHasNoFallThrough(MachineBasicBlock &MBB) const {
708 if (MBB.empty()) return false;
710 switch (MBB.back().getOpcode()) {
711 case X86::RET: // Return.
716 case X86::JMP: // Uncond branch.
717 case X86::JMP32r: // Indirect branch.
718 case X86::JMP64r: // Indirect branch (64-bit).
719 case X86::JMP32m: // Indirect branch through mem.
720 case X86::JMP64m: // Indirect branch through mem (64-bit).
722 default: return false;
727 ReverseBranchCondition(std::vector<MachineOperand> &Cond) const {
728 assert(Cond.size() == 1 && "Invalid X86 branch condition!");
729 Cond[0].setImm(GetOppositeBranchCondition((X86::CondCode)Cond[0].getImm()));
733 const TargetRegisterClass *X86InstrInfo::getPointerRegClass() const {
734 const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
735 if (Subtarget->is64Bit())
736 return &X86::GR64RegClass;
738 return &X86::GR32RegClass;