From 359b65f782cc323daba4f8c5c21c70a98c9d40ea Mon Sep 17 00:00:00 2001 From: Alkis Evlogimenos Date: Sat, 13 Dec 2003 05:36:22 +0000 Subject: [PATCH] Add a floating point killer pass. This pass runs before register allocaton on the X86 to add information to the machine code denoting that our floating point stackifier cannot handle virtual point register that are alive across basic blocks. This pass adds an implicit def of all virtual floating point register at the end of each basic block. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10446 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/FloatingPoint.cpp | 52 +++++++++++++++++++++++++++++ lib/Target/X86/X86.h | 6 ++++ lib/Target/X86/X86FloatingPoint.cpp | 52 +++++++++++++++++++++++++++++ lib/Target/X86/X86TargetMachine.cpp | 10 ++++++ 4 files changed, 120 insertions(+) diff --git a/lib/Target/X86/FloatingPoint.cpp b/lib/Target/X86/FloatingPoint.cpp index 5c6e6ebfdde..b6bae6dffae 100644 --- a/lib/Target/X86/FloatingPoint.cpp +++ b/lib/Target/X86/FloatingPoint.cpp @@ -18,6 +18,7 @@ #include "llvm/CodeGen/MachineFunctionPass.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/LiveVariables.h" +#include "llvm/CodeGen/Passes.h" #include "llvm/Target/TargetInstrInfo.h" #include "llvm/Target/TargetMachine.h" #include "Support/Debug.h" @@ -601,4 +602,55 @@ void FPS::handleSpecialFP(MachineBasicBlock::iterator &I) { I = MBB->erase(I)-1; // Remove the pseudo instruction } +namespace { + + struct FPK : public MachineFunctionPass { + virtual const char *getPassName() const { return "X86 FP Killer"; } + virtual bool runOnMachineFunction(MachineFunction &MF); + virtual void getAnalysisUsage(AnalysisUsage &AU) const { + AU.setPreservesAll(); + AU.addRequired(); + AU.addRequiredID(PHIEliminationID); + MachineFunctionPass::getAnalysisUsage(AU); + } + }; +} + +FunctionPass * createX86FloatingPointKillerPass() { return new FPK(); } + +bool FPK::runOnMachineFunction(MachineFunction &MF) +{ + const TargetInstrInfo& tii = MF.getTarget().getInstrInfo();; + + for (MachineFunction::iterator + mbbi = MF.begin(), mbbe = MF.end(); mbbi != mbbe; ++mbbi) { + MachineBasicBlock& mbb = *mbbi; + MachineBasicBlock::reverse_iterator mii = mbb.rbegin(); + // rewind to the last non terminating instruction + while (mii != mbb.rend() && tii.isTerminatorInstr((*mii)->getOpcode())) { + ++mii; + } + // add implicit def for all virtual floating point registers so that + // they are spilled at the end of each basic block, since our + // register stackifier doesn't handle them otherwise. + MachineInstr* instr = BuildMI(X86::IMPLICIT_DEF, 7) + .addReg(X86::FP6, MOTy::Def) + .addReg(X86::FP5, MOTy::Def) + .addReg(X86::FP4, MOTy::Def) + .addReg(X86::FP3, MOTy::Def) + .addReg(X86::FP2, MOTy::Def) + .addReg(X86::FP1, MOTy::Def) + .addReg(X86::FP0, MOTy::Def); + + mbb.insert(mii.base(), instr); + LiveVariables& lv = getAnalysis(); + for (unsigned i = 0; i < instr->getNumOperands(); ++i) { + lv.HandlePhysRegDef(instr->getOperand(i).getAllocatedRegNum(), instr); + // force live variables to compute that these registers are dead + lv.HandlePhysRegDef(instr->getOperand(i).getAllocatedRegNum(), 0); + } + } + return true; +} + } // End llvm namespace diff --git a/lib/Target/X86/X86.h b/lib/Target/X86/X86.h index c474d18ead3..35845fb0380 100644 --- a/lib/Target/X86/X86.h +++ b/lib/Target/X86/X86.h @@ -44,6 +44,12 @@ FunctionPass *createX86SSAPeepholeOptimizerPass(); /// FunctionPass *createX86PeepholeOptimizerPass(); +/// createX86FloatingPointKiller - This function returns a pass which +/// kills every floating point register at the end of each basic block +/// because our FloatingPointStackifier cannot handle them. +/// +FunctionPass *createX86FloatingPointKillerPass(); + /// createX86FloatingPointStackifierPass - This function returns a pass which /// converts floating point register references and pseudo instructions into /// floating point stack references and physical instructions. diff --git a/lib/Target/X86/X86FloatingPoint.cpp b/lib/Target/X86/X86FloatingPoint.cpp index 5c6e6ebfdde..b6bae6dffae 100644 --- a/lib/Target/X86/X86FloatingPoint.cpp +++ b/lib/Target/X86/X86FloatingPoint.cpp @@ -18,6 +18,7 @@ #include "llvm/CodeGen/MachineFunctionPass.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/LiveVariables.h" +#include "llvm/CodeGen/Passes.h" #include "llvm/Target/TargetInstrInfo.h" #include "llvm/Target/TargetMachine.h" #include "Support/Debug.h" @@ -601,4 +602,55 @@ void FPS::handleSpecialFP(MachineBasicBlock::iterator &I) { I = MBB->erase(I)-1; // Remove the pseudo instruction } +namespace { + + struct FPK : public MachineFunctionPass { + virtual const char *getPassName() const { return "X86 FP Killer"; } + virtual bool runOnMachineFunction(MachineFunction &MF); + virtual void getAnalysisUsage(AnalysisUsage &AU) const { + AU.setPreservesAll(); + AU.addRequired(); + AU.addRequiredID(PHIEliminationID); + MachineFunctionPass::getAnalysisUsage(AU); + } + }; +} + +FunctionPass * createX86FloatingPointKillerPass() { return new FPK(); } + +bool FPK::runOnMachineFunction(MachineFunction &MF) +{ + const TargetInstrInfo& tii = MF.getTarget().getInstrInfo();; + + for (MachineFunction::iterator + mbbi = MF.begin(), mbbe = MF.end(); mbbi != mbbe; ++mbbi) { + MachineBasicBlock& mbb = *mbbi; + MachineBasicBlock::reverse_iterator mii = mbb.rbegin(); + // rewind to the last non terminating instruction + while (mii != mbb.rend() && tii.isTerminatorInstr((*mii)->getOpcode())) { + ++mii; + } + // add implicit def for all virtual floating point registers so that + // they are spilled at the end of each basic block, since our + // register stackifier doesn't handle them otherwise. + MachineInstr* instr = BuildMI(X86::IMPLICIT_DEF, 7) + .addReg(X86::FP6, MOTy::Def) + .addReg(X86::FP5, MOTy::Def) + .addReg(X86::FP4, MOTy::Def) + .addReg(X86::FP3, MOTy::Def) + .addReg(X86::FP2, MOTy::Def) + .addReg(X86::FP1, MOTy::Def) + .addReg(X86::FP0, MOTy::Def); + + mbb.insert(mii.base(), instr); + LiveVariables& lv = getAnalysis(); + for (unsigned i = 0; i < instr->getNumOperands(); ++i) { + lv.HandlePhysRegDef(instr->getOperand(i).getAllocatedRegNum(), instr); + // force live variables to compute that these registers are dead + lv.HandlePhysRegDef(instr->getOperand(i).getAllocatedRegNum(), 0); + } + } + return true; +} + } // End llvm namespace diff --git a/lib/Target/X86/X86TargetMachine.cpp b/lib/Target/X86/X86TargetMachine.cpp index eb4d19a7783..fba8e8dc9ea 100644 --- a/lib/Target/X86/X86TargetMachine.cpp +++ b/lib/Target/X86/X86TargetMachine.cpp @@ -76,6 +76,11 @@ bool X86TargetMachine::addPassesToEmitAssembly(PassManager &PM, if (PrintCode) PM.add(createMachineFunctionPrinterPass()); + // kill floating point registers at the end of basic blocks. this is + // done because the floating point register stackifier cannot handle + // floating point regs that are live across basic blocks. + PM.add(createX86FloatingPointKillerPass()); + // Perform register allocation to convert to a concrete x86 representation PM.add(createRegisterAllocator()); @@ -129,6 +134,11 @@ bool X86TargetMachine::addPassesToJITCompile(FunctionPassManager &PM) { if (PrintCode) PM.add(createMachineFunctionPrinterPass()); + // kill floating point registers at the end of basic blocks. this is + // done because the floating point register stackifier cannot handle + // floating point regs that are live across basic blocks. + PM.add(createX86FloatingPointKillerPass()); + // Perform register allocation to convert to a concrete x86 representation PM.add(createRegisterAllocator());