Ugh, perform an optimization that GCC should be able to do itself. This

speeds up livevar from .48/.32s -> .45/.31s in LLC on perlbmk

llvm-svn: 11217

1 files changed, 7 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/LiveVariables.cpp b/llvm/lib/CodeGen/LiveVariables.cpp
index eafbb1c18a3..a8627396ccc 100644
--- a/llvm/lib/CodeGen/LiveVariables.cpp
+++ b/llvm/lib/CodeGen/LiveVariables.cpp
@@ -146,14 +146,15 @@ void LiveVariables::HandlePhysRegDef(unsigned Reg, MachineInstr *MI) {
 
   for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
        *AliasSet; ++AliasSet) {
-    if (MachineInstr *LastUse = PhysRegInfo[*AliasSet]) {
-      if (PhysRegUsed[*AliasSet])
-	RegistersKilled.insert(std::make_pair(LastUse, *AliasSet));
+    unsigned Alias = *AliasSet;
+    if (MachineInstr *LastUse = PhysRegInfo[Alias]) {
+      if (PhysRegUsed[Alias])
+	RegistersKilled.insert(std::make_pair(LastUse, Alias));
       else
-	RegistersDead.insert(std::make_pair(LastUse, *AliasSet));
+	RegistersDead.insert(std::make_pair(LastUse, Alias));
     }
-    PhysRegInfo[*AliasSet] = MI;
-    PhysRegUsed[*AliasSet] = false;
+    PhysRegInfo[Alias] = MI;
+    PhysRegUsed[Alias] = false;
   }
 }