Switch this from using an std::map to using a DenseMap. This speeds up
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
diff --git a/lib/CodeGen/PHIElimination.cpp b/lib/CodeGen/PHIElimination.cpp
index 5457ded..ba0c977 100644
--- a/lib/CodeGen/PHIElimination.cpp
+++ b/lib/CodeGen/PHIElimination.cpp
@@ -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 @@
// 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 @@
}
// 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,