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Switch this from using an std::map to using a DenseMap. This speeds up

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phi-elimination from 0.6 to 0.54s on kc++.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13454 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-05-10 19:17:36 +00:00
parent 80e20eb487
commit 8abf69374e
1 changed files with 5 additions and 6 deletions
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11
lib/CodeGen/PHIElimination.cpp
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@ -20,6 +20,7 @@
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "Support/DenseMap.h"
#include "Support/STLExtras.h"
using namespace llvm;
@ -70,7 +71,8 @@ bool PNE::EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB) {
// VRegPHIUseCount - Keep track of the number of times each virtual register
// is used by PHI nodes in this block.
std::map<unsigned, unsigned> VRegPHIUseCount;
DenseMap<unsigned, VirtReg2IndexFunctor> VRegPHIUseCount;
VRegPHIUseCount.grow(MF.getSSARegMap()->getLastVirtReg());
// Get an iterator to the first instruction after the last PHI node (this may
// allso be the end of the basic block). While we are scanning the PHIs,
@ -231,11 +233,8 @@ bool PNE::EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB) {
}
// Is it used by any PHI instructions in this block?
if (!ValueIsLive) {
std::map<unsigned,unsigned>::iterator I =
VRegPHIUseCount.find(SrcReg);
ValueIsLive = I != VRegPHIUseCount.end() && I->second;
}
if (!ValueIsLive)
ValueIsLive = VRegPHIUseCount[SrcReg] != 0;
}
// Okay, if we now know that the value is not live out of the block,