}
}
-static X86::CondCode GetCondFromBranchOpc(unsigned BrOpc) {
+static X86::CondCode getCondFromBranchOpc(unsigned BrOpc) {
switch (BrOpc) {
default: return X86::COND_INVALID;
case X86::JE_4: return X86::COND_E;
}
}
+/// getCondFromSETOpc - return condition code of a SET opcode.
+static X86::CondCode getCondFromSETOpc(unsigned Opc) {
+ switch (Opc) {
+ default: return X86::COND_INVALID;
+ case X86::SETAr: case X86::SETAm: return X86::COND_A;
+ case X86::SETAEr: case X86::SETAEm: return X86::COND_AE;
+ case X86::SETBr: case X86::SETBm: return X86::COND_B;
+ case X86::SETBEr: case X86::SETBEm: return X86::COND_BE;
+ case X86::SETEr: case X86::SETEm: return X86::COND_E;
+ case X86::SETGr: case X86::SETGm: return X86::COND_G;
+ case X86::SETGEr: case X86::SETGEm: return X86::COND_GE;
+ case X86::SETLr: case X86::SETLm: return X86::COND_L;
+ case X86::SETLEr: case X86::SETLEm: return X86::COND_LE;
+ case X86::SETNEr: case X86::SETNEm: return X86::COND_NE;
+ case X86::SETNOr: case X86::SETNOm: return X86::COND_NO;
+ case X86::SETNPr: case X86::SETNPm: return X86::COND_NP;
+ case X86::SETNSr: case X86::SETNSm: return X86::COND_NS;
+ case X86::SETOr: case X86::SETOm: return X86::COND_O;
+ case X86::SETPr: case X86::SETPm: return X86::COND_P;
+ case X86::SETSr: case X86::SETSm: return X86::COND_S;
+ }
+}
+
+/// getCondFromCmovOpc - return condition code of a CMov opcode.
+static X86::CondCode getCondFromCMovOpc(unsigned Opc) {
+ switch (Opc) {
+ default: return X86::COND_INVALID;
+ case X86::CMOVA16rm: case X86::CMOVA16rr: case X86::CMOVA32rm:
+ case X86::CMOVA32rr: case X86::CMOVA64rm: case X86::CMOVA64rr:
+ return X86::COND_A;
+ case X86::CMOVAE16rm: case X86::CMOVAE16rr: case X86::CMOVAE32rm:
+ case X86::CMOVAE32rr: case X86::CMOVAE64rm: case X86::CMOVAE64rr:
+ return X86::COND_AE;
+ case X86::CMOVB16rm: case X86::CMOVB16rr: case X86::CMOVB32rm:
+ case X86::CMOVB32rr: case X86::CMOVB64rm: case X86::CMOVB64rr:
+ return X86::COND_B;
+ case X86::CMOVBE16rm: case X86::CMOVBE16rr: case X86::CMOVBE32rm:
+ case X86::CMOVBE32rr: case X86::CMOVBE64rm: case X86::CMOVBE64rr:
+ return X86::COND_BE;
+ case X86::CMOVE16rm: case X86::CMOVE16rr: case X86::CMOVE32rm:
+ case X86::CMOVE32rr: case X86::CMOVE64rm: case X86::CMOVE64rr:
+ return X86::COND_E;
+ case X86::CMOVG16rm: case X86::CMOVG16rr: case X86::CMOVG32rm:
+ case X86::CMOVG32rr: case X86::CMOVG64rm: case X86::CMOVG64rr:
+ return X86::COND_G;
+ case X86::CMOVGE16rm: case X86::CMOVGE16rr: case X86::CMOVGE32rm:
+ case X86::CMOVGE32rr: case X86::CMOVGE64rm: case X86::CMOVGE64rr:
+ return X86::COND_GE;
+ case X86::CMOVL16rm: case X86::CMOVL16rr: case X86::CMOVL32rm:
+ case X86::CMOVL32rr: case X86::CMOVL64rm: case X86::CMOVL64rr:
+ return X86::COND_L;
+ case X86::CMOVLE16rm: case X86::CMOVLE16rr: case X86::CMOVLE32rm:
+ case X86::CMOVLE32rr: case X86::CMOVLE64rm: case X86::CMOVLE64rr:
+ return X86::COND_LE;
+ case X86::CMOVNE16rm: case X86::CMOVNE16rr: case X86::CMOVNE32rm:
+ case X86::CMOVNE32rr: case X86::CMOVNE64rm: case X86::CMOVNE64rr:
+ return X86::COND_NE;
+ case X86::CMOVNO16rm: case X86::CMOVNO16rr: case X86::CMOVNO32rm:
+ case X86::CMOVNO32rr: case X86::CMOVNO64rm: case X86::CMOVNO64rr:
+ return X86::COND_NO;
+ case X86::CMOVNP16rm: case X86::CMOVNP16rr: case X86::CMOVNP32rm:
+ case X86::CMOVNP32rr: case X86::CMOVNP64rm: case X86::CMOVNP64rr:
+ return X86::COND_NP;
+ case X86::CMOVNS16rm: case X86::CMOVNS16rr: case X86::CMOVNS32rm:
+ case X86::CMOVNS32rr: case X86::CMOVNS64rm: case X86::CMOVNS64rr:
+ return X86::COND_NS;
+ case X86::CMOVO16rm: case X86::CMOVO16rr: case X86::CMOVO32rm:
+ case X86::CMOVO32rr: case X86::CMOVO64rm: case X86::CMOVO64rr:
+ return X86::COND_O;
+ case X86::CMOVP16rm: case X86::CMOVP16rr: case X86::CMOVP32rm:
+ case X86::CMOVP32rr: case X86::CMOVP64rm: case X86::CMOVP64rr:
+ return X86::COND_P;
+ case X86::CMOVS16rm: case X86::CMOVS16rr: case X86::CMOVS32rm:
+ case X86::CMOVS32rr: case X86::CMOVS64rm: case X86::CMOVS64rr:
+ return X86::COND_S;
+ }
+}
+
unsigned X86::GetCondBranchFromCond(X86::CondCode CC) {
switch (CC) {
default: llvm_unreachable("Illegal condition code!");
}
}
-/// getCMovFromCond - Return a cmov(rr) opcode for the given condition and
-/// register size in bytes.
-static unsigned getCMovFromCond(X86::CondCode CC, unsigned RegBytes) {
- static const unsigned Opc[16][3] = {
+/// getSwappedCondition - assume the flags are set by MI(a,b), return
+/// the condition code if we modify the instructions such that flags are
+/// set by MI(b,a).
+X86::CondCode getSwappedCondition(X86::CondCode CC) {
+ switch (CC) {
+ default: return X86::COND_INVALID;
+ case X86::COND_E: return X86::COND_E;
+ case X86::COND_NE: return X86::COND_NE;
+ case X86::COND_L: return X86::COND_G;
+ case X86::COND_LE: return X86::COND_GE;
+ case X86::COND_G: return X86::COND_L;
+ case X86::COND_GE: return X86::COND_LE;
+ case X86::COND_B: return X86::COND_A;
+ case X86::COND_BE: return X86::COND_AE;
+ case X86::COND_A: return X86::COND_B;
+ case X86::COND_AE: return X86::COND_BE;
+ }
+}
+
+/// getSETFromCond - Return a set opcode for the given condition and
+/// whether it has memory operand.
+static unsigned getSETFromCond(X86::CondCode CC,
+ bool HasMemoryOperand) {
+ static const unsigned Opc[16][2] = {
+ { X86::SETAr, X86::SETAm },
+ { X86::SETAEr, X86::SETAEm },
+ { X86::SETBr, X86::SETBm },
+ { X86::SETBEr, X86::SETBEm },
+ { X86::SETEr, X86::SETEm },
+ { X86::SETGr, X86::SETGm },
+ { X86::SETGEr, X86::SETGEm },
+ { X86::SETLr, X86::SETLm },
+ { X86::SETLEr, X86::SETLEm },
+ { X86::SETNEr, X86::SETNEm },
+ { X86::SETNOr, X86::SETNOm },
+ { X86::SETNPr, X86::SETNPm },
+ { X86::SETNSr, X86::SETNSm },
+ { X86::SETOr, X86::SETOm },
+ { X86::SETPr, X86::SETPm },
+ { X86::SETSr, X86::SETSm }
+ };
+
+ assert(CC < 16 && "Can only handle standard cond codes");
+ return Opc[CC][HasMemoryOperand ? 1 : 0];
+}
+
+/// getCMovFromCond - Return a cmov opcode for the given condition,
+/// register size in bytes, and operand type.
+static unsigned getCMovFromCond(X86::CondCode CC, unsigned RegBytes,
+ bool HasMemoryOperand) {
+ static const unsigned Opc[32][3] = {
{ X86::CMOVA16rr, X86::CMOVA32rr, X86::CMOVA64rr },
{ X86::CMOVAE16rr, X86::CMOVAE32rr, X86::CMOVAE64rr },
{ X86::CMOVB16rr, X86::CMOVB32rr, X86::CMOVB64rr },
{ X86::CMOVNS16rr, X86::CMOVNS32rr, X86::CMOVNS64rr },
{ X86::CMOVO16rr, X86::CMOVO32rr, X86::CMOVO64rr },
{ X86::CMOVP16rr, X86::CMOVP32rr, X86::CMOVP64rr },
- { X86::CMOVS16rr, X86::CMOVS32rr, X86::CMOVS64rr }
+ { X86::CMOVS16rr, X86::CMOVS32rr, X86::CMOVS64rr },
+ { X86::CMOVA16rm, X86::CMOVA32rm, X86::CMOVA64rm },
+ { X86::CMOVAE16rm, X86::CMOVAE32rm, X86::CMOVAE64rm },
+ { X86::CMOVB16rm, X86::CMOVB32rm, X86::CMOVB64rm },
+ { X86::CMOVBE16rm, X86::CMOVBE32rm, X86::CMOVBE64rm },
+ { X86::CMOVE16rm, X86::CMOVE32rm, X86::CMOVE64rm },
+ { X86::CMOVG16rm, X86::CMOVG32rm, X86::CMOVG64rm },
+ { X86::CMOVGE16rm, X86::CMOVGE32rm, X86::CMOVGE64rm },
+ { X86::CMOVL16rm, X86::CMOVL32rm, X86::CMOVL64rm },
+ { X86::CMOVLE16rm, X86::CMOVLE32rm, X86::CMOVLE64rm },
+ { X86::CMOVNE16rm, X86::CMOVNE32rm, X86::CMOVNE64rm },
+ { X86::CMOVNO16rm, X86::CMOVNO32rm, X86::CMOVNO64rm },
+ { X86::CMOVNP16rm, X86::CMOVNP32rm, X86::CMOVNP64rm },
+ { X86::CMOVNS16rm, X86::CMOVNS32rm, X86::CMOVNS64rm },
+ { X86::CMOVO16rm, X86::CMOVO32rm, X86::CMOVO64rm },
+ { X86::CMOVP16rm, X86::CMOVP32rm, X86::CMOVP64rm },
+ { X86::CMOVS16rm, X86::CMOVS32rm, X86::CMOVS64rm }
};
assert(CC < 16 && "Can only handle standard cond codes");
+ unsigned Idx = HasMemoryOperand ? 16+CC : CC;
switch(RegBytes) {
default: llvm_unreachable("Illegal register size!");
- case 2: return Opc[CC][0];
- case 4: return Opc[CC][1];
- case 8: return Opc[CC][2];
+ case 2: return Opc[Idx][0];
+ case 4: return Opc[Idx][1];
+ case 8: return Opc[Idx][2];
}
}
}
// Handle conditional branches.
- X86::CondCode BranchCode = GetCondFromBranchOpc(I->getOpcode());
+ X86::CondCode BranchCode = getCondFromBranchOpc(I->getOpcode());
if (BranchCode == X86::COND_INVALID)
return true; // Can't handle indirect branch.
if (I->isDebugValue())
continue;
if (I->getOpcode() != X86::JMP_4 &&
- GetCondFromBranchOpc(I->getOpcode()) == X86::COND_INVALID)
+ getCondFromBranchOpc(I->getOpcode()) == X86::COND_INVALID)
break;
// Remove the branch.
I->eraseFromParent();
MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
assert(Cond.size() == 1 && "Invalid Cond array");
unsigned Opc = getCMovFromCond((X86::CondCode)Cond[0].getImm(),
- MRI.getRegClass(DstReg)->getSize());
+ MRI.getRegClass(DstReg)->getSize(),
+ false/*HasMemoryOperand*/);
BuildMI(MBB, I, DL, get(Opc), DstReg).addReg(FalseReg).addReg(TrueReg);
}
NewMIs.push_back(MIB);
}
+bool X86InstrInfo::
+analyzeCompare(const MachineInstr *MI, unsigned &SrcReg, unsigned &SrcReg2,
+ int &CmpMask, int &CmpValue) const {
+ switch (MI->getOpcode()) {
+ default: break;
+ case X86::CMP64ri32:
+ case X86::CMP64ri8:
+ case X86::CMP32ri:
+ case X86::CMP32ri8:
+ case X86::CMP16ri:
+ case X86::CMP16ri8:
+ case X86::CMP8ri:
+ SrcReg = MI->getOperand(0).getReg();
+ SrcReg2 = 0;
+ CmpMask = ~0;
+ CmpValue = MI->getOperand(1).getImm();
+ return true;
+ case X86::CMP64rr:
+ case X86::CMP32rr:
+ case X86::CMP16rr:
+ case X86::CMP8rr:
+ SrcReg = MI->getOperand(0).getReg();
+ SrcReg2 = MI->getOperand(1).getReg();
+ CmpMask = ~0;
+ CmpValue = 0;
+ return true;
+ }
+ return false;
+}
+
+/// isRedundantFlagInstr - check whether the first instruction, whose only
+/// purpose is to update flags, can be made redundant.
+/// CMPrr can be made redundant by SUBrr if the operands are the same.
+/// This function can be extended later on.
+/// SrcReg, SrcRegs: register operands for FlagI.
+/// ImmValue: immediate for FlagI if it takes an immediate.
+inline static bool isRedundantFlagInstr(MachineInstr *FlagI, unsigned SrcReg,
+ unsigned SrcReg2, int ImmValue,
+ MachineInstr *OI) {
+ if (((FlagI->getOpcode() == X86::CMP64rr &&
+ OI->getOpcode() == X86::SUB64rr) ||
+ (FlagI->getOpcode() == X86::CMP32rr &&
+ OI->getOpcode() == X86::SUB32rr)||
+ (FlagI->getOpcode() == X86::CMP16rr &&
+ OI->getOpcode() == X86::SUB16rr)||
+ (FlagI->getOpcode() == X86::CMP8rr &&
+ OI->getOpcode() == X86::SUB8rr)) &&
+ ((OI->getOperand(1).getReg() == SrcReg &&
+ OI->getOperand(2).getReg() == SrcReg2) ||
+ (OI->getOperand(1).getReg() == SrcReg2 &&
+ OI->getOperand(2).getReg() == SrcReg)))
+ return true;
+
+ if (((FlagI->getOpcode() == X86::CMP64ri32 &&
+ OI->getOpcode() == X86::SUB64ri32) ||
+ (FlagI->getOpcode() == X86::CMP64ri8 &&
+ OI->getOpcode() == X86::SUB64ri8) ||
+ (FlagI->getOpcode() == X86::CMP32ri &&
+ OI->getOpcode() == X86::SUB32ri) ||
+ (FlagI->getOpcode() == X86::CMP32ri8 &&
+ OI->getOpcode() == X86::SUB32ri8) ||
+ (FlagI->getOpcode() == X86::CMP16ri &&
+ OI->getOpcode() == X86::SUB16ri) ||
+ (FlagI->getOpcode() == X86::CMP16ri8 &&
+ OI->getOpcode() == X86::SUB16ri8) ||
+ (FlagI->getOpcode() == X86::CMP8ri &&
+ OI->getOpcode() == X86::SUB8ri)) &&
+ OI->getOperand(1).getReg() == SrcReg &&
+ OI->getOperand(2).getImm() == ImmValue)
+ return true;
+ return false;
+}
+
+/// optimizeCompareInstr - Check if there exists an earlier instruction that
+/// operates on the same source operands and sets flags in the same way as
+/// Compare; remove Compare if possible.
+bool X86InstrInfo::
+optimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg, unsigned SrcReg2,
+ int CmpMask, int CmpValue,
+ const MachineRegisterInfo *MRI) const {
+ // Get the unique definition of SrcReg.
+ MachineInstr *MI = MRI->getUniqueVRegDef(SrcReg);
+ if (!MI) return false;
+
+ // CmpInstr is the first instruction of the BB.
+ MachineBasicBlock::iterator I = CmpInstr, Def = MI;
+
+ // We are searching for an earlier instruction that can make CmpInstr
+ // redundant and that instruction will be saved in Sub.
+ MachineInstr *Sub = NULL;
+ const TargetRegisterInfo *TRI = &getRegisterInfo();
+
+ // We iterate backward, starting from the instruction before CmpInstr and
+ // stop when reaching the definition of a source register or done with the BB.
+ // RI points to the instruction before CmpInstr.
+ // If the definition is in this basic block, RE points to the definition;
+ // otherwise, RE is the rend of the basic block.
+ MachineBasicBlock::reverse_iterator
+ RI = MachineBasicBlock::reverse_iterator(I),
+ RE = CmpInstr->getParent() == MI->getParent() ?
+ MachineBasicBlock::reverse_iterator(++Def) /* points to MI */ :
+ CmpInstr->getParent()->rend();
+ for (; RI != RE; ++RI) {
+ MachineInstr *Instr = &*RI;
+ // Check whether CmpInstr can be made redundant by the current instruction.
+ if (isRedundantFlagInstr(CmpInstr, SrcReg, SrcReg2, CmpValue, Instr)) {
+ Sub = Instr;
+ break;
+ }
+
+ if (Instr->modifiesRegister(X86::EFLAGS, TRI) ||
+ Instr->readsRegister(X86::EFLAGS, TRI))
+ // This instruction modifies or uses EFLAGS.
+ // We can't remove CmpInstr.
+ return false;
+ }
+
+ // Return false if no candidates exist.
+ if (!Sub)
+ return false;
+
+ bool IsSwapped = (SrcReg2 != 0 && Sub->getOperand(1).getReg() == SrcReg2 &&
+ Sub->getOperand(2).getReg() == SrcReg);
+
+ // Scan forward from the instruction after CmpInstr for uses of EFLAGS.
+ // It is safe to remove CmpInstr if EFLAGS is redefined or killed.
+ // If we are done with the basic block, we need to check whether EFLAGS is
+ // live-out.
+ bool IsSafe = false;
+ SmallVector<std::pair<MachineInstr*, unsigned /*NewOpc*/>, 4> OpsToUpdate;
+ MachineBasicBlock::iterator E = CmpInstr->getParent()->end();
+ for (++I; I != E; ++I) {
+ const MachineInstr &Instr = *I;
+ if (Instr.modifiesRegister(X86::EFLAGS, TRI)) {
+ // It is safe to remove CmpInstr if EFLAGS is updated again.
+ IsSafe = true;
+ break;
+ }
+ if (!Instr.readsRegister(X86::EFLAGS, TRI))
+ continue;
+
+ // EFLAGS is used by this instruction.
+ if (IsSwapped) {
+ // If we have SUB(r1, r2) and CMP(r2, r1), the condition code needs
+ // to be changed from r2 > r1 to r1 < r2, from r2 < r1 to r1 > r2, etc.
+ // We decode the condition code from opcode, swap the condition code,
+ // and synthesize the new opcode.
+ bool OpcIsSET = false;
+ X86::CondCode OldCC;
+ if (Instr.isBranch())
+ OldCC = getCondFromBranchOpc(Instr.getOpcode());
+ else {
+ OldCC = getCondFromSETOpc(Instr.getOpcode());
+ if (OldCC != X86::COND_INVALID)
+ OpcIsSET = true;
+ else
+ OldCC = getCondFromCMovOpc(Instr.getOpcode());
+ }
+ if (OldCC == X86::COND_INVALID) return false;
+ X86::CondCode NewCC = getSwappedCondition(OldCC);
+ if (NewCC == X86::COND_INVALID) return false;
+
+ // Synthesize the new opcode.
+ bool HasMemoryOperand = Instr.hasOneMemOperand();
+ unsigned NewOpc;
+ if (Instr.isBranch())
+ NewOpc = GetCondBranchFromCond(NewCC);
+ else if(OpcIsSET)
+ NewOpc = getSETFromCond(NewCC, HasMemoryOperand);
+ else {
+ unsigned DstReg = Instr.getOperand(0).getReg();
+ NewOpc = getCMovFromCond(NewCC, MRI->getRegClass(DstReg)->getSize(),
+ HasMemoryOperand);
+ }
+
+ // Push the MachineInstr to OpsToUpdate.
+ // If it is safe to remove CmpInstr, the condition code of these
+ // instructions will be modified.
+ OpsToUpdate.push_back(std::make_pair(&*I, NewOpc));
+ }
+ if (Instr.killsRegister(X86::EFLAGS, TRI)) {
+ IsSafe = true;
+ break;
+ }
+ }
+
+ // If EFLAGS is not killed nor re-defined, we should check whether it is
+ // live-out. If it is live-out, do not optimize.
+ if (IsSwapped && !IsSafe) {
+ MachineBasicBlock *MBB = CmpInstr->getParent();
+ for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
+ SE = MBB->succ_end(); SI != SE; ++SI)
+ if ((*SI)->isLiveIn(X86::EFLAGS))
+ return false;
+ }
+
+ // Make sure Sub instruction defines EFLAGS.
+ assert(Sub->getNumOperands() >= 4 && Sub->getOperand(3).isReg() &&
+ Sub->getOperand(3).getReg() == X86::EFLAGS &&
+ "EFLAGS should be the 4th operand of SUBrr or SUBri.");
+ Sub->getOperand(3).setIsDef(true);
+ CmpInstr->eraseFromParent();
+
+ // Modify the condition code of instructions in OpsToUpdate.
+ for (unsigned i = 0, e = OpsToUpdate.size(); i < e; i++)
+ OpsToUpdate[i].first->setDesc(get(OpsToUpdate[i].second));
+ return true;
+}
+
/// Expand2AddrUndef - Expand a single-def pseudo instruction to a two-addr
/// instruction with two undef reads of the register being defined. This is
/// used for mapping:
projects / oota-llvm.git / blobdiff