[llvm] r192602 - Basic blocks typically have few predecessors. Use a SmallDenseMap to

[Chris Lattner]

Author: lattner
Date: Mon Oct 14 11:05:55 2013
New Revision: 192602

URL: http://llvm.org/viewvc/llvm-project?rev=192602&view=rev
Log:
Basic blocks typically have few predecessors.  Use a SmallDenseMap to
avoid a heap allocation when this is the case.

Modified:
    llvm/trunk/lib/Transforms/Utils/SSAUpdater.cpp

Modified: llvm/trunk/lib/Transforms/Utils/SSAUpdater.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SSAUpdater.cpp?rev=192602&r1=192601&r2=192602&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SSAUpdater.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SSAUpdater.cpp Mon Oct 14 11:05:55 2013
@@ -63,7 +63,7 @@ void SSAUpdater::AddAvailableValue(Basic
 }
 
 static bool IsEquivalentPHI(PHINode *PHI,
-                            DenseMap<BasicBlock*, Value*> &ValueMapping) {
+                          SmallDenseMap<BasicBlock*, Value*, 8> &ValueMapping) {
   unsigned PHINumValues = PHI->getNumIncomingValues();
   if (PHINumValues != ValueMapping.size())
     return false;
@@ -136,8 +136,8 @@ Value *SSAUpdater::GetValueInMiddleOfBlo
   // Otherwise, we do need a PHI: check to see if we already have one available
   // in this block that produces the right value.
   if (isa<PHINode>(BB->begin())) {
-    DenseMap<BasicBlock*, Value*> ValueMapping(PredValues.begin(),
-                                               PredValues.end());
+    SmallDenseMap<BasicBlock*, Value*, 8> ValueMapping(PredValues.begin(),
+                                                       PredValues.end());
     PHINode *SomePHI;
     for (BasicBlock::iterator It = BB->begin();
          (SomePHI = dyn_cast<PHINode>(It)); ++It) {