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[AArch64] Use MachineRegisterInfo instead of LiveIntervals to calculate liveness. NFC. 

The CondOpt pass currently uses LiveIntervals to set the dead flag on a def.  This patch uses MachineRegisterInfo::use_empty instead as that is equivalent to the def being dead.

This removes an instance of LiveIntervals in the pass manager pipeline and saves 3.8% of compile time on llc conpiled for AArch64.

Reviewed by Chad Rosier and Zhaoshi.

llvm-svn: 235532
This commit is contained in:
Pete Cooper 2015-04-22 18:05:13 +00:00
parent c96ee08016
commit 037b700b7f
1 changed files with 4 additions and 4 deletions
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8
llvm/lib/Target/AArch64/AArch64ConditionOptimizer.cpp
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@ -67,6 +67,7 @@
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
@ -86,6 +87,7 @@ namespace {
class AArch64ConditionOptimizer : public MachineFunctionPass {
const TargetInstrInfo *TII;
MachineDominatorTree *DomTree;
const MachineRegisterInfo *MRI;
public:
// Stores immediate, compare instruction opcode and branch condition (in this
@ -116,7 +118,6 @@ void initializeAArch64ConditionOptimizerPass(PassRegistry &);
INITIALIZE_PASS_BEGIN(AArch64ConditionOptimizer, "aarch64-condopt",
"AArch64 CondOpt Pass", false, false)
INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
INITIALIZE_PASS_END(AArch64ConditionOptimizer, "aarch64-condopt",
"AArch64 CondOpt Pass", false, false)
@ -127,8 +128,6 @@ FunctionPass *llvm::createAArch64ConditionOptimizerPass() {
void AArch64ConditionOptimizer::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<MachineDominatorTree>();
AU.addPreserved<MachineDominatorTree>();
AU.addRequired<LiveIntervals>();
AU.addPreserved<LiveIntervals>();
MachineFunctionPass::getAnalysisUsage(AU);
}
@ -155,7 +154,7 @@ MachineInstr *AArch64ConditionOptimizer::findSuitableCompare(
// cmn is an alias for adds with a dead destination register.
case AArch64::ADDSWri:
case AArch64::ADDSXri:
if (I->getOperand(0).isDead())
if (MRI->use_empty(I->getOperand(0).getReg()))
return I;
DEBUG(dbgs() << "Destination of cmp is not dead, " << *I << '\n');
@ -306,6 +305,7 @@ bool AArch64ConditionOptimizer::runOnMachineFunction(MachineFunction &MF) {
<< "********** Function: " << MF.getName() << '\n');
TII = MF.getSubtarget().getInstrInfo();
DomTree = &getAnalysis<MachineDominatorTree>();
MRI = &MF.getRegInfo();
bool Changed = false;