From fae02a2ab19abdf12854356e19aeb1da62a0b8ea Mon Sep 17 00:00:00 2001 From: Lang Hames Date: Tue, 21 Jul 2009 23:47:33 +0000 Subject: [PATCH] Exposed PHIElimination pass within CodeGen. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76688 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/PHIElimination.cpp | 95 ++++++++++-------------------------------- lib/CodeGen/PHIElimination.h | 80 +++++++++++++++++++++++++++++++++++ 2 files changed, 101 insertions(+), 74 deletions(-) create mode 100644 lib/CodeGen/PHIElimination.h diff --git a/lib/CodeGen/PHIElimination.cpp b/lib/CodeGen/PHIElimination.cpp index c5c76fc7946..dc799e8c27f 100644 --- a/lib/CodeGen/PHIElimination.cpp +++ b/lib/CodeGen/PHIElimination.cpp @@ -14,6 +14,7 @@ //===----------------------------------------------------------------------===// #define DEBUG_TYPE "phielim" +#include "PHIElimination.h" #include "llvm/BasicBlock.h" #include "llvm/Instructions.h" #include "llvm/CodeGen/LiveVariables.h" @@ -22,7 +23,6 @@ #include "llvm/CodeGen/MachineInstr.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineRegisterInfo.h" -#include "llvm/Target/TargetInstrInfo.h" #include "llvm/Target/TargetMachine.h" #include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/STLExtras.h" @@ -34,76 +34,20 @@ using namespace llvm; STATISTIC(NumAtomic, "Number of atomic phis lowered"); -namespace { - class VISIBILITY_HIDDEN PNE : public MachineFunctionPass { - MachineRegisterInfo *MRI; // Machine register information - - public: - static char ID; // Pass identification, replacement for typeid - PNE() : MachineFunctionPass(&ID) {} - - virtual bool runOnMachineFunction(MachineFunction &Fn); - - virtual void getAnalysisUsage(AnalysisUsage &AU) const { - AU.addPreserved(); - AU.addPreservedID(MachineLoopInfoID); - AU.addPreservedID(MachineDominatorsID); - MachineFunctionPass::getAnalysisUsage(AU); - } - - private: - /// EliminatePHINodes - Eliminate phi nodes by inserting copy instructions - /// in predecessor basic blocks. - /// - bool EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB); - void LowerAtomicPHINode(MachineBasicBlock &MBB, - MachineBasicBlock::iterator AfterPHIsIt); - - /// analyzePHINodes - Gather information about the PHI nodes in - /// here. In particular, we want to map the number of uses of a virtual - /// register which is used in a PHI node. We map that to the BB the - /// vreg is coming from. This is used later to determine when the vreg - /// is killed in the BB. - /// - void analyzePHINodes(const MachineFunction& Fn); - - // FindCopyInsertPoint - Find a safe place in MBB to insert a copy from - // SrcReg. This needs to be after any def or uses of SrcReg, but before - // any subsequent point where control flow might jump out of the basic - // block. - MachineBasicBlock::iterator FindCopyInsertPoint(MachineBasicBlock &MBB, - unsigned SrcReg); - - // SkipPHIsAndLabels - Copies need to be inserted after phi nodes and - // also after any exception handling labels: in landing pads execution - // starts at the label, so any copies placed before it won't be executed! - MachineBasicBlock::iterator SkipPHIsAndLabels(MachineBasicBlock &MBB, - MachineBasicBlock::iterator I) { - // Rather than assuming that EH labels come before other kinds of labels, - // just skip all labels. - while (I != MBB.end() && - (I->getOpcode() == TargetInstrInfo::PHI || I->isLabel())) - ++I; - return I; - } - - typedef std::pair BBVRegPair; - typedef std::map VRegPHIUse; - - VRegPHIUse VRegPHIUseCount; - - // Defs of PHI sources which are implicit_def. - SmallPtrSet ImpDefs; - }; -} - -char PNE::ID = 0; -static RegisterPass +char PHIElimination::ID = 0; +static RegisterPass X("phi-node-elimination", "Eliminate PHI nodes for register allocation"); const PassInfo *const llvm::PHIEliminationID = &X; -bool PNE::runOnMachineFunction(MachineFunction &Fn) { +void llvm::PHIElimination::getAnalysisUsage(AnalysisUsage &AU) const { + AU.addPreserved(); + AU.addPreservedID(MachineLoopInfoID); + AU.addPreservedID(MachineDominatorsID); + MachineFunctionPass::getAnalysisUsage(AU); + } + +bool llvm::PHIElimination::runOnMachineFunction(MachineFunction &Fn) { MRI = &Fn.getRegInfo(); analyzePHINodes(Fn); @@ -132,7 +76,8 @@ bool PNE::runOnMachineFunction(MachineFunction &Fn) { /// EliminatePHINodes - Eliminate phi nodes by inserting copy instructions in /// predecessor basic blocks. /// -bool PNE::EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB) { +bool llvm::PHIElimination::EliminatePHINodes(MachineFunction &MF, + MachineBasicBlock &MBB) { if (MBB.empty() || MBB.front().getOpcode() != TargetInstrInfo::PHI) return false; // Quick exit for basic blocks without PHIs. @@ -162,8 +107,9 @@ static bool isSourceDefinedByImplicitDef(const MachineInstr *MPhi, // FindCopyInsertPoint - Find a safe place in MBB to insert a copy from SrcReg. // This needs to be after any def or uses of SrcReg, but before any subsequent // point where control flow might jump out of the basic block. -MachineBasicBlock::iterator PNE::FindCopyInsertPoint(MachineBasicBlock &MBB, - unsigned SrcReg) { +MachineBasicBlock::iterator +llvm::PHIElimination::FindCopyInsertPoint(MachineBasicBlock &MBB, + unsigned SrcReg) { // Handle the trivial case trivially. if (MBB.empty()) return MBB.begin(); @@ -206,9 +152,10 @@ MachineBasicBlock::iterator PNE::FindCopyInsertPoint(MachineBasicBlock &MBB, /// under the assuption that it needs to be lowered in a way that supports /// atomic execution of PHIs. This lowering method is always correct all of the /// time. -/// -void PNE::LowerAtomicPHINode(MachineBasicBlock &MBB, - MachineBasicBlock::iterator AfterPHIsIt) { +/// +void llvm::PHIElimination::LowerAtomicPHINode( + MachineBasicBlock &MBB, + MachineBasicBlock::iterator AfterPHIsIt) { // Unlink the PHI node from the basic block, but don't delete the PHI yet. MachineInstr *MPhi = MBB.remove(MBB.begin()); @@ -420,7 +367,7 @@ void PNE::LowerAtomicPHINode(MachineBasicBlock &MBB, /// used in a PHI node. We map that to the BB the vreg is coming from. This is /// used later to determine when the vreg is killed in the BB. /// -void PNE::analyzePHINodes(const MachineFunction& Fn) { +void llvm::PHIElimination::analyzePHINodes(const MachineFunction& Fn) { for (MachineFunction::const_iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) for (MachineBasicBlock::const_iterator BBI = I->begin(), BBE = I->end(); diff --git a/lib/CodeGen/PHIElimination.h b/lib/CodeGen/PHIElimination.h new file mode 100644 index 00000000000..26a37316eb8 --- /dev/null +++ b/lib/CodeGen/PHIElimination.h @@ -0,0 +1,80 @@ +//===-- lib/CodeGen/PHIElimination.h ----------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CODEGEN_PHIELIMINATION_HPP +#define LLVM_CODEGEN_PHIELIMINATION_HPP + +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/CodeGen/MachineFunctionPass.h" +#include "llvm/Target/TargetInstrInfo.h" + +#include + +namespace llvm { + + /// Lower PHI instructions to copies. + class PHIElimination : public MachineFunctionPass { + MachineRegisterInfo *MRI; // Machine register information + + public: + static char ID; // Pass identification, replacement for typeid + PHIElimination() : MachineFunctionPass(&ID) {} + + virtual bool runOnMachineFunction(MachineFunction &Fn); + + virtual void getAnalysisUsage(AnalysisUsage &AU) const; + + private: + /// EliminatePHINodes - Eliminate phi nodes by inserting copy instructions + /// in predecessor basic blocks. + /// + bool EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB); + void LowerAtomicPHINode(MachineBasicBlock &MBB, + MachineBasicBlock::iterator AfterPHIsIt); + + /// analyzePHINodes - Gather information about the PHI nodes in + /// here. In particular, we want to map the number of uses of a virtual + /// register which is used in a PHI node. We map that to the BB the + /// vreg is coming from. This is used later to determine when the vreg + /// is killed in the BB. + /// + void analyzePHINodes(const MachineFunction& Fn); + + // FindCopyInsertPoint - Find a safe place in MBB to insert a copy from + // SrcReg. This needs to be after any def or uses of SrcReg, but before + // any subsequent point where control flow might jump out of the basic + // block. + MachineBasicBlock::iterator FindCopyInsertPoint(MachineBasicBlock &MBB, + unsigned SrcReg); + + // SkipPHIsAndLabels - Copies need to be inserted after phi nodes and + // also after any exception handling labels: in landing pads execution + // starts at the label, so any copies placed before it won't be executed! + MachineBasicBlock::iterator SkipPHIsAndLabels(MachineBasicBlock &MBB, + MachineBasicBlock::iterator I) { + // Rather than assuming that EH labels come before other kinds of labels, + // just skip all labels. + while (I != MBB.end() && + (I->getOpcode() == TargetInstrInfo::PHI || I->isLabel())) + ++I; + return I; + } + + typedef std::pair BBVRegPair; + typedef std::map VRegPHIUse; + + VRegPHIUse VRegPHIUseCount; + + // Defs of PHI sources which are implicit_def. + SmallPtrSet ImpDefs; + }; + +} + +#endif /* PHIELIMINATION_H */ -- 2.11.0