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author | Stephen Hines <srhines@google.com> | 2014-04-23 16:57:46 -0700 |
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committer | Stephen Hines <srhines@google.com> | 2014-04-24 15:53:16 -0700 |
commit | 36b56886974eae4f9c5ebc96befd3e7bfe5de338 (patch) | |
tree | e6cfb69fbbd937f450eeb83bfb83b9da3b01275a /lib/CodeGen/MachineCopyPropagation.cpp | |
parent | 69a8640022b04415ae9fac62f8ab090601d8f889 (diff) | |
download | external_llvm-36b56886974eae4f9c5ebc96befd3e7bfe5de338.zip external_llvm-36b56886974eae4f9c5ebc96befd3e7bfe5de338.tar.gz external_llvm-36b56886974eae4f9c5ebc96befd3e7bfe5de338.tar.bz2 |
Update to LLVM 3.5a.
Change-Id: Ifadecab779f128e62e430c2b4f6ddd84953ed617
Diffstat (limited to 'lib/CodeGen/MachineCopyPropagation.cpp')
-rw-r--r-- | lib/CodeGen/MachineCopyPropagation.cpp | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/lib/CodeGen/MachineCopyPropagation.cpp b/lib/CodeGen/MachineCopyPropagation.cpp index 4f48e2c..7e1970c 100644 --- a/lib/CodeGen/MachineCopyPropagation.cpp +++ b/lib/CodeGen/MachineCopyPropagation.cpp @@ -42,7 +42,7 @@ namespace { initializeMachineCopyPropagationPass(*PassRegistry::getPassRegistry()); } - virtual bool runOnMachineFunction(MachineFunction &MF); + bool runOnMachineFunction(MachineFunction &MF) override; private: typedef SmallVector<unsigned, 4> DestList; @@ -127,13 +127,10 @@ static bool isNopCopy(MachineInstr *CopyMI, unsigned Def, unsigned Src, } // Remove MI from the function because it has been determined it is dead. -// Turn it into a noop KILL instruction if it has super-register liveness -// adjustments. +// Turn it into a noop KILL instruction as opposed to removing it to +// maintain imp-use/imp-def chains. void MachineCopyPropagation::removeCopy(MachineInstr *MI) { - if (MI->getNumOperands() == 2) - MI->eraseFromParent(); - else - MI->setDesc(TII->get(TargetOpcode::KILL)); + MI->setDesc(TII->get(TargetOpcode::KILL)); } bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) { @@ -142,6 +139,8 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) { DenseMap<unsigned, MachineInstr*> CopyMap; // Def -> copies map SourceMap SrcMap; // Src -> Def map + DEBUG(dbgs() << "MCP: CopyPropagateBlock " << MBB.getName() << "\n"); + bool Changed = false; for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ) { MachineInstr *MI = &*I; @@ -176,6 +175,8 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) { // CALL // %RAX<def> = COPY %RSP + DEBUG(dbgs() << "MCP: copy is a NOP, removing: "; MI->dump()); + // Clear any kills of Def between CopyMI and MI. This extends the // live range. for (MachineBasicBlock::iterator I = CopyMI, E = MI; I != E; ++I) @@ -191,10 +192,14 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) { // If Src is defined by a previous copy, it cannot be eliminated. for (MCRegAliasIterator AI(Src, TRI, true); AI.isValid(); ++AI) { CI = CopyMap.find(*AI); - if (CI != CopyMap.end()) + if (CI != CopyMap.end()) { + DEBUG(dbgs() << "MCP: Copy is no longer dead: "; CI->second->dump()); MaybeDeadCopies.remove(CI->second); + } } + DEBUG(dbgs() << "MCP: Copy is a deletion candidate: "; MI->dump()); + // Copy is now a candidate for deletion. MaybeDeadCopies.insert(MI); @@ -255,8 +260,10 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) { // for elimination. for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) { DenseMap<unsigned, MachineInstr*>::iterator CI = CopyMap.find(*AI); - if (CI != CopyMap.end()) + if (CI != CopyMap.end()) { + DEBUG(dbgs() << "MCP: Copy is used - not dead: "; CI->second->dump()); MaybeDeadCopies.remove(CI->second); + } } } @@ -273,6 +280,8 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) { unsigned Reg = (*DI)->getOperand(0).getReg(); if (MRI->isReserved(Reg) || !MaskMO.clobbersPhysReg(Reg)) continue; + DEBUG(dbgs() << "MCP: Removing copy due to regmask clobbering: "; + (*DI)->dump()); removeCopy(*DI); Changed = true; ++NumDeletes; @@ -320,6 +329,9 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) { } bool MachineCopyPropagation::runOnMachineFunction(MachineFunction &MF) { + if (skipOptnoneFunction(*MF.getFunction())) + return false; + bool Changed = false; TRI = MF.getTarget().getRegisterInfo(); |