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/CodeGen/MachineInstrBuilder.h"
23 X86InstrInfo::X86InstrInfo(X86TargetMachine &tm)
24 : TargetInstrInfo(X86Insts, sizeof(X86Insts)/sizeof(X86Insts[0])),
25 TM(tm), RI(tm, *this) {
28 /// getDWARF_LABELOpcode - Return the opcode of the target's DWARF_LABEL
29 /// instruction if it has one. This is used by codegen passes that update
30 /// DWARF line number info as they modify the code.
31 unsigned X86InstrInfo::getDWARF_LABELOpcode() const {
32 return X86::DWARF_LABEL;
36 bool X86InstrInfo::isMoveInstr(const MachineInstr& MI,
38 unsigned& destReg) const {
39 MachineOpCode oc = MI.getOpcode();
40 if (oc == X86::MOV8rr || oc == X86::MOV16rr ||
41 oc == X86::MOV32rr || oc == X86::MOV64rr ||
42 oc == X86::MOV16to16_ || oc == X86::MOV32to32_ ||
43 oc == X86::FpMOV || oc == X86::MOVSSrr || oc == X86::MOVSDrr ||
44 oc == X86::FsMOVAPSrr || oc == X86::FsMOVAPDrr ||
45 oc == X86::MOVAPSrr || oc == X86::MOVAPDrr ||
46 oc == X86::MOVSS2PSrr || oc == X86::MOVSD2PDrr ||
47 oc == X86::MOVPS2SSrr || oc == X86::MOVPD2SDrr) {
48 assert(MI.getNumOperands() == 2 &&
49 MI.getOperand(0).isRegister() &&
50 MI.getOperand(1).isRegister() &&
51 "invalid register-register move instruction");
52 sourceReg = MI.getOperand(1).getReg();
53 destReg = MI.getOperand(0).getReg();
59 unsigned X86InstrInfo::isLoadFromStackSlot(MachineInstr *MI,
60 int &FrameIndex) const {
61 switch (MI->getOpcode()) {
74 if (MI->getOperand(1).isFrameIndex() && MI->getOperand(2).isImmediate() &&
75 MI->getOperand(3).isRegister() && MI->getOperand(4).isImmediate() &&
76 MI->getOperand(2).getImmedValue() == 1 &&
77 MI->getOperand(3).getReg() == 0 &&
78 MI->getOperand(4).getImmedValue() == 0) {
79 FrameIndex = MI->getOperand(1).getFrameIndex();
80 return MI->getOperand(0).getReg();
87 unsigned X86InstrInfo::isStoreToStackSlot(MachineInstr *MI,
88 int &FrameIndex) const {
89 switch (MI->getOpcode()) {
102 if (MI->getOperand(0).isFrameIndex() && MI->getOperand(1).isImmediate() &&
103 MI->getOperand(2).isRegister() && MI->getOperand(3).isImmediate() &&
104 MI->getOperand(1).getImmedValue() == 1 &&
105 MI->getOperand(2).getReg() == 0 &&
106 MI->getOperand(3).getImmedValue() == 0) {
107 FrameIndex = MI->getOperand(0).getFrameIndex();
108 return MI->getOperand(4).getReg();
116 /// convertToThreeAddress - This method must be implemented by targets that
117 /// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
118 /// may be able to convert a two-address instruction into a true
119 /// three-address instruction on demand. This allows the X86 target (for
120 /// example) to convert ADD and SHL instructions into LEA instructions if they
121 /// would require register copies due to two-addressness.
123 /// This method returns a null pointer if the transformation cannot be
124 /// performed, otherwise it returns the new instruction.
126 MachineInstr *X86InstrInfo::convertToThreeAddress(MachineInstr *MI) const {
127 // All instructions input are two-addr instructions. Get the known operands.
128 unsigned Dest = MI->getOperand(0).getReg();
129 unsigned Src = MI->getOperand(1).getReg();
131 MachineInstr *NewMI = NULL;
132 switch (MI->getOpcode()) {
134 case X86::SHUFPSrri: {
135 assert(MI->getNumOperands() == 4 && "Unknown shufps instruction!");
136 const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
137 unsigned A = MI->getOperand(0).getReg();
138 unsigned B = MI->getOperand(1).getReg();
139 unsigned C = MI->getOperand(2).getReg();
140 unsigned M = MI->getOperand(3).getImmedValue();
141 if (!Subtarget->hasSSE2() || B != C) return 0;
142 NewMI = BuildMI(get(X86::PSHUFDri), A).addReg(B).addImm(M);
143 NewMI->copyKillDeadInfo(MI);
148 // FIXME: None of these instructions are promotable to LEAs without
149 // additional information. In particular, LEA doesn't set the flags that
150 // add and inc do. :(
153 // FIXME: 16-bit LEA's are really slow on Athlons, but not bad on P4's. When
154 // we have subtarget support, enable the 16-bit LEA generation here.
155 bool DisableLEA16 = true;
157 switch (MI->getOpcode()) {
160 assert(MI->getNumOperands() == 2 && "Unknown inc instruction!");
161 NewMI = addRegOffset(BuildMI(get(X86::LEA32r), Dest), Src, 1);
165 if (DisableLEA16) return 0;
166 assert(MI->getNumOperands() == 2 && "Unknown inc instruction!");
167 NewMI = addRegOffset(BuildMI(get(X86::LEA16r), Dest), Src, 1);
171 assert(MI->getNumOperands() == 2 && "Unknown dec instruction!");
172 NewMI = addRegOffset(BuildMI(get(X86::LEA32r), Dest), Src, -1);
176 if (DisableLEA16) return 0;
177 assert(MI->getNumOperands() == 2 && "Unknown dec instruction!");
178 NewMI = addRegOffset(BuildMI(get(X86::LEA16r), Dest), Src, -1);
181 assert(MI->getNumOperands() == 3 && "Unknown add instruction!");
182 NewMI = addRegReg(BuildMI(get(X86::LEA32r), Dest), Src,
183 MI->getOperand(2).getReg());
186 if (DisableLEA16) return 0;
187 assert(MI->getNumOperands() == 3 && "Unknown add instruction!");
188 NewMI = addRegReg(BuildMI(get(X86::LEA16r), Dest), Src,
189 MI->getOperand(2).getReg());
193 assert(MI->getNumOperands() == 3 && "Unknown add instruction!");
194 if (MI->getOperand(2).isImmediate())
195 NewMI = addRegOffset(BuildMI(get(X86::LEA32r), Dest), Src,
196 MI->getOperand(2).getImmedValue());
200 if (DisableLEA16) return 0;
201 assert(MI->getNumOperands() == 3 && "Unknown add instruction!");
202 if (MI->getOperand(2).isImmediate())
203 NewMI = addRegOffset(BuildMI(get(X86::LEA16r), Dest), Src,
204 MI->getOperand(2).getImmedValue());
207 if (DisableLEA16) return 0;
209 assert(MI->getNumOperands() == 3 && MI->getOperand(2).isImmediate() &&
210 "Unknown shl instruction!");
211 unsigned ShAmt = MI->getOperand(2).getImmedValue();
212 if (ShAmt == 1 || ShAmt == 2 || ShAmt == 3) {
214 AM.Scale = 1 << ShAmt;
216 unsigned Opc = MI->getOpcode() == X86::SHL32ri ? X86::LEA32r :X86::LEA16r;
217 NewMI = addFullAddress(BuildMI(get(Opc), Dest), AM);
223 NewMI->copyKillDeadInfo(MI);
227 /// commuteInstruction - We have a few instructions that must be hacked on to
230 MachineInstr *X86InstrInfo::commuteInstruction(MachineInstr *MI) const {
231 // FIXME: Can commute cmoves by changing the condition!
232 switch (MI->getOpcode()) {
233 case X86::SHRD16rri8: // A = SHRD16rri8 B, C, I -> A = SHLD16rri8 C, B, (16-I)
234 case X86::SHLD16rri8: // A = SHLD16rri8 B, C, I -> A = SHRD16rri8 C, B, (16-I)
235 case X86::SHRD32rri8: // A = SHRD32rri8 B, C, I -> A = SHLD32rri8 C, B, (32-I)
236 case X86::SHLD32rri8:{// A = SHLD32rri8 B, C, I -> A = SHRD32rri8 C, B, (32-I)
239 switch (MI->getOpcode()) {
240 default: assert(0 && "Unreachable!");
241 case X86::SHRD16rri8: Size = 16; Opc = X86::SHLD16rri8; break;
242 case X86::SHLD16rri8: Size = 16; Opc = X86::SHRD16rri8; break;
243 case X86::SHRD32rri8: Size = 32; Opc = X86::SHLD32rri8; break;
244 case X86::SHLD32rri8: Size = 32; Opc = X86::SHRD32rri8; break;
246 unsigned Amt = MI->getOperand(3).getImmedValue();
247 unsigned A = MI->getOperand(0).getReg();
248 unsigned B = MI->getOperand(1).getReg();
249 unsigned C = MI->getOperand(2).getReg();
250 bool BisKill = MI->getOperand(1).isKill();
251 bool CisKill = MI->getOperand(2).isKill();
252 return BuildMI(get(Opc), A).addReg(C, false, false, CisKill)
253 .addReg(B, false, false, BisKill).addImm(Size-Amt);
256 return TargetInstrInfo::commuteInstruction(MI);
260 static X86::CondCode GetCondFromBranchOpc(unsigned BrOpc) {
262 default: return X86::COND_INVALID;
263 case X86::JE: return X86::COND_E;
264 case X86::JNE: return X86::COND_NE;
265 case X86::JL: return X86::COND_L;
266 case X86::JLE: return X86::COND_LE;
267 case X86::JG: return X86::COND_G;
268 case X86::JGE: return X86::COND_GE;
269 case X86::JB: return X86::COND_B;
270 case X86::JBE: return X86::COND_BE;
271 case X86::JA: return X86::COND_A;
272 case X86::JAE: return X86::COND_AE;
273 case X86::JS: return X86::COND_S;
274 case X86::JNS: return X86::COND_NS;
275 case X86::JP: return X86::COND_P;
276 case X86::JNP: return X86::COND_NP;
277 case X86::JO: return X86::COND_O;
278 case X86::JNO: return X86::COND_NO;
282 unsigned X86::GetCondBranchFromCond(X86::CondCode CC) {
284 default: assert(0 && "Illegal condition code!");
285 case X86::COND_E: return X86::JE;
286 case X86::COND_NE: return X86::JNE;
287 case X86::COND_L: return X86::JL;
288 case X86::COND_LE: return X86::JLE;
289 case X86::COND_G: return X86::JG;
290 case X86::COND_GE: return X86::JGE;
291 case X86::COND_B: return X86::JB;
292 case X86::COND_BE: return X86::JBE;
293 case X86::COND_A: return X86::JA;
294 case X86::COND_AE: return X86::JAE;
295 case X86::COND_S: return X86::JS;
296 case X86::COND_NS: return X86::JNS;
297 case X86::COND_P: return X86::JP;
298 case X86::COND_NP: return X86::JNP;
299 case X86::COND_O: return X86::JO;
300 case X86::COND_NO: return X86::JNO;
304 /// GetOppositeBranchCondition - Return the inverse of the specified condition,
305 /// e.g. turning COND_E to COND_NE.
306 X86::CondCode X86::GetOppositeBranchCondition(X86::CondCode CC) {
308 default: assert(0 && "Illegal condition code!");
309 case X86::COND_E: return X86::COND_NE;
310 case X86::COND_NE: return X86::COND_E;
311 case X86::COND_L: return X86::COND_GE;
312 case X86::COND_LE: return X86::COND_G;
313 case X86::COND_G: return X86::COND_LE;
314 case X86::COND_GE: return X86::COND_L;
315 case X86::COND_B: return X86::COND_AE;
316 case X86::COND_BE: return X86::COND_A;
317 case X86::COND_A: return X86::COND_BE;
318 case X86::COND_AE: return X86::COND_B;
319 case X86::COND_S: return X86::COND_NS;
320 case X86::COND_NS: return X86::COND_S;
321 case X86::COND_P: return X86::COND_NP;
322 case X86::COND_NP: return X86::COND_P;
323 case X86::COND_O: return X86::COND_NO;
324 case X86::COND_NO: return X86::COND_O;
329 bool X86InstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,
330 MachineBasicBlock *&TBB,
331 MachineBasicBlock *&FBB,
332 std::vector<MachineOperand> &Cond) const {
333 // TODO: If FP_REG_KILL is around, ignore it.
335 // If the block has no terminators, it just falls into the block after it.
336 MachineBasicBlock::iterator I = MBB.end();
337 if (I == MBB.begin() || !isTerminatorInstr((--I)->getOpcode()))
340 // Get the last instruction in the block.
341 MachineInstr *LastInst = I;
343 // If there is only one terminator instruction, process it.
344 if (I == MBB.begin() || !isTerminatorInstr((--I)->getOpcode())) {
345 if (!isBranch(LastInst->getOpcode()))
348 // If the block ends with a branch there are 3 possibilities:
349 // it's an unconditional, conditional, or indirect branch.
351 if (LastInst->getOpcode() == X86::JMP) {
352 TBB = LastInst->getOperand(0).getMachineBasicBlock();
355 X86::CondCode BranchCode = GetCondFromBranchOpc(LastInst->getOpcode());
356 if (BranchCode == X86::COND_INVALID)
357 return true; // Can't handle indirect branch.
359 // Otherwise, block ends with fall-through condbranch.
360 TBB = LastInst->getOperand(0).getMachineBasicBlock();
361 Cond.push_back(MachineOperand::CreateImm(BranchCode));
365 // Get the instruction before it if it's a terminator.
366 MachineInstr *SecondLastInst = I;
368 // If there are three terminators, we don't know what sort of block this is.
369 if (SecondLastInst && I != MBB.begin() &&
370 isTerminatorInstr((--I)->getOpcode()))
373 // If the block ends with X86::JMP and a conditional branch, handle it.
374 X86::CondCode BranchCode = GetCondFromBranchOpc(SecondLastInst->getOpcode());
375 if (BranchCode != X86::COND_INVALID && LastInst->getOpcode() == X86::JMP) {
376 TBB = SecondLastInst->getOperand(0).getMachineBasicBlock();
377 Cond.push_back(MachineOperand::CreateImm(BranchCode));
378 FBB = LastInst->getOperand(0).getMachineBasicBlock();
382 // Otherwise, can't handle this.
386 void X86InstrInfo::RemoveBranch(MachineBasicBlock &MBB) const {
387 MachineBasicBlock::iterator I = MBB.end();
388 if (I == MBB.begin()) return;
390 if (I->getOpcode() != X86::JMP &&
391 GetCondFromBranchOpc(I->getOpcode()) == X86::COND_INVALID)
394 // Remove the branch.
395 I->eraseFromParent();
399 if (I == MBB.begin()) return;
401 if (GetCondFromBranchOpc(I->getOpcode()) == X86::COND_INVALID)
404 // Remove the branch.
405 I->eraseFromParent();
408 void X86InstrInfo::InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
409 MachineBasicBlock *FBB,
410 const std::vector<MachineOperand> &Cond) const {
411 // Shouldn't be a fall through.
412 assert(TBB && "InsertBranch must not be told to insert a fallthrough");
413 assert((Cond.size() == 1 || Cond.size() == 0) &&
414 "X86 branch conditions have one component!");
416 if (FBB == 0) { // One way branch.
418 // Unconditional branch?
419 BuildMI(&MBB, get(X86::JMP)).addMBB(TBB);
421 // Conditional branch.
422 unsigned Opc = GetCondBranchFromCond((X86::CondCode)Cond[0].getImm());
423 BuildMI(&MBB, get(Opc)).addMBB(TBB);
428 // Two-way Conditional branch.
429 unsigned Opc = GetCondBranchFromCond((X86::CondCode)Cond[0].getImm());
430 BuildMI(&MBB, get(Opc)).addMBB(TBB);
431 BuildMI(&MBB, get(X86::JMP)).addMBB(FBB);
434 bool X86InstrInfo::BlockHasNoFallThrough(MachineBasicBlock &MBB) const {
435 if (MBB.empty()) return false;
437 switch (MBB.back().getOpcode()) {
438 case X86::JMP: // Uncond branch.
439 case X86::JMP32r: // Indirect branch.
440 case X86::JMP32m: // Indirect branch through mem.
442 default: return false;
447 ReverseBranchCondition(std::vector<MachineOperand> &Cond) const {
448 assert(Cond.size() == 1 && "Invalid X86 branch condition!");
449 Cond[0].setImm(GetOppositeBranchCondition((X86::CondCode)Cond[0].getImm()));
453 const TargetRegisterClass *X86InstrInfo::getPointerRegClass() const {
454 const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
455 if (Subtarget->is64Bit())
456 return &X86::GR64RegClass;
458 return &X86::GR32RegClass;