diff options
Diffstat (limited to 'llvm/lib/Target/X86/X86FlagsCopyLowering.cpp')
| -rw-r--r-- | llvm/lib/Target/X86/X86FlagsCopyLowering.cpp | 92 |
1 files changed, 84 insertions, 8 deletions
diff --git a/llvm/lib/Target/X86/X86FlagsCopyLowering.cpp b/llvm/lib/Target/X86/X86FlagsCopyLowering.cpp index cfba06fb6533..b1d2de29c896 100644 --- a/llvm/lib/Target/X86/X86FlagsCopyLowering.cpp +++ b/llvm/lib/Target/X86/X86FlagsCopyLowering.cpp @@ -87,12 +87,12 @@ public: static char ID; private: - MachineRegisterInfo *MRI; - const X86Subtarget *Subtarget; - const X86InstrInfo *TII; - const TargetRegisterInfo *TRI; - const TargetRegisterClass *PromoteRC; - MachineDominatorTree *MDT; + MachineRegisterInfo *MRI = nullptr; + const X86Subtarget *Subtarget = nullptr; + const X86InstrInfo *TII = nullptr; + const TargetRegisterInfo *TRI = nullptr; + const TargetRegisterClass *PromoteRC = nullptr; + MachineDominatorTree *MDT = nullptr; CondRegArray collectCondsInRegs(MachineBasicBlock &MBB, MachineBasicBlock::iterator CopyDefI); @@ -115,6 +115,10 @@ private: MachineBasicBlock::iterator TestPos, DebugLoc TestLoc, MachineInstr &CMovI, MachineOperand &FlagUse, CondRegArray &CondRegs); + void rewriteFCMov(MachineBasicBlock &TestMBB, + MachineBasicBlock::iterator TestPos, DebugLoc TestLoc, + MachineInstr &CMovI, MachineOperand &FlagUse, + CondRegArray &CondRegs); void rewriteCondJmp(MachineBasicBlock &TestMBB, MachineBasicBlock::iterator TestPos, DebugLoc TestLoc, MachineInstr &JmpI, CondRegArray &CondRegs); @@ -334,6 +338,28 @@ static MachineBasicBlock &splitBlock(MachineBasicBlock &MBB, return NewMBB; } +static X86::CondCode getCondFromFCMOV(unsigned Opcode) { + switch (Opcode) { + default: return X86::COND_INVALID; + case X86::CMOVBE_Fp32: case X86::CMOVBE_Fp64: case X86::CMOVBE_Fp80: + return X86::COND_BE; + case X86::CMOVB_Fp32: case X86::CMOVB_Fp64: case X86::CMOVB_Fp80: + return X86::COND_B; + case X86::CMOVE_Fp32: case X86::CMOVE_Fp64: case X86::CMOVE_Fp80: + return X86::COND_E; + case X86::CMOVNBE_Fp32: case X86::CMOVNBE_Fp64: case X86::CMOVNBE_Fp80: + return X86::COND_A; + case X86::CMOVNB_Fp32: case X86::CMOVNB_Fp64: case X86::CMOVNB_Fp80: + return X86::COND_AE; + case X86::CMOVNE_Fp32: case X86::CMOVNE_Fp64: case X86::CMOVNE_Fp80: + return X86::COND_NE; + case X86::CMOVNP_Fp32: case X86::CMOVNP_Fp64: case X86::CMOVNP_Fp80: + return X86::COND_NP; + case X86::CMOVP_Fp32: case X86::CMOVP_Fp64: case X86::CMOVP_Fp80: + return X86::COND_P; + } +} + bool X86FlagsCopyLoweringPass::runOnMachineFunction(MachineFunction &MF) { LLVM_DEBUG(dbgs() << "********** " << getPassName() << " : " << MF.getName() << " **********\n"); @@ -593,6 +619,8 @@ bool X86FlagsCopyLoweringPass::runOnMachineFunction(MachineFunction &MF) { // Otherwise we can just rewrite in-place. if (X86::getCondFromCMov(MI) != X86::COND_INVALID) { rewriteCMov(*TestMBB, TestPos, TestLoc, MI, *FlagUse, CondRegs); + } else if (getCondFromFCMOV(MI.getOpcode()) != X86::COND_INVALID) { + rewriteFCMov(*TestMBB, TestPos, TestLoc, MI, *FlagUse, CondRegs); } else if (X86::getCondFromSETCC(MI) != X86::COND_INVALID) { rewriteSetCC(*TestMBB, TestPos, TestLoc, MI, *FlagUse, CondRegs); } else if (MI.getOpcode() == TargetOpcode::COPY) { @@ -674,6 +702,9 @@ bool X86FlagsCopyLoweringPass::runOnMachineFunction(MachineFunction &MF) { } Blocks.push_back(SuccMBB); + + // After this, EFLAGS will be recreated before each use. + SuccMBB->removeLiveIn(X86::EFLAGS); } } while (!Blocks.empty()); @@ -779,10 +810,10 @@ void X86FlagsCopyLoweringPass::rewriteArithmetic( CondRegArray &CondRegs) { // Arithmetic is either reading CF or OF. Figure out which condition we need // to preserve in a register. - X86::CondCode Cond; + X86::CondCode Cond = X86::COND_INVALID; // The addend to use to reset CF or OF when added to the flag value. - int Addend; + int Addend = 0; switch (getMnemonicFromOpcode(MI.getOpcode())) { case FlagArithMnemonic::ADC: @@ -852,6 +883,51 @@ void X86FlagsCopyLoweringPass::rewriteCMov(MachineBasicBlock &TestMBB, LLVM_DEBUG(dbgs() << " fixed cmov: "; CMovI.dump()); } +void X86FlagsCopyLoweringPass::rewriteFCMov(MachineBasicBlock &TestMBB, + MachineBasicBlock::iterator TestPos, + DebugLoc TestLoc, + MachineInstr &CMovI, + MachineOperand &FlagUse, + CondRegArray &CondRegs) { + // First get the register containing this specific condition. + X86::CondCode Cond = getCondFromFCMOV(CMovI.getOpcode()); + unsigned CondReg; + bool Inverted; + std::tie(CondReg, Inverted) = + getCondOrInverseInReg(TestMBB, TestPos, TestLoc, Cond, CondRegs); + + MachineBasicBlock &MBB = *CMovI.getParent(); + + // Insert a direct test of the saved register. + insertTest(MBB, CMovI.getIterator(), CMovI.getDebugLoc(), CondReg); + + auto getFCMOVOpcode = [](unsigned Opcode, bool Inverted) { + switch (Opcode) { + default: llvm_unreachable("Unexpected opcode!"); + case X86::CMOVBE_Fp32: case X86::CMOVNBE_Fp32: + case X86::CMOVB_Fp32: case X86::CMOVNB_Fp32: + case X86::CMOVE_Fp32: case X86::CMOVNE_Fp32: + case X86::CMOVP_Fp32: case X86::CMOVNP_Fp32: + return Inverted ? X86::CMOVE_Fp32 : X86::CMOVNE_Fp32; + case X86::CMOVBE_Fp64: case X86::CMOVNBE_Fp64: + case X86::CMOVB_Fp64: case X86::CMOVNB_Fp64: + case X86::CMOVE_Fp64: case X86::CMOVNE_Fp64: + case X86::CMOVP_Fp64: case X86::CMOVNP_Fp64: + return Inverted ? X86::CMOVE_Fp64 : X86::CMOVNE_Fp64; + case X86::CMOVBE_Fp80: case X86::CMOVNBE_Fp80: + case X86::CMOVB_Fp80: case X86::CMOVNB_Fp80: + case X86::CMOVE_Fp80: case X86::CMOVNE_Fp80: + case X86::CMOVP_Fp80: case X86::CMOVNP_Fp80: + return Inverted ? X86::CMOVE_Fp80 : X86::CMOVNE_Fp80; + } + }; + + // Rewrite the CMov to use the !ZF flag from the test. + CMovI.setDesc(TII->get(getFCMOVOpcode(CMovI.getOpcode(), Inverted))); + FlagUse.setIsKill(true); + LLVM_DEBUG(dbgs() << " fixed fcmov: "; CMovI.dump()); +} + void X86FlagsCopyLoweringPass::rewriteCondJmp( MachineBasicBlock &TestMBB, MachineBasicBlock::iterator TestPos, DebugLoc TestLoc, MachineInstr &JmpI, CondRegArray &CondRegs) { |