switch DominanceFrontier::splitBlock to use a smallvector for

the pred list instead of a vector, saving a boat load of malloc/free's.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79062 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/VMCore/Dominators.cpp b/lib/VMCore/Dominators.cpp
index 735a70c509275cb33ae8a4b6b1494919d9852bec..9b6f5c2c946e5ad8bf95390ca47ce7da49898f4c 100644 (file)
--- a/lib/VMCore/Dominators.cpp
+++ b/lib/VMCore/Dominators.cpp
@@ -76,7 +76,7 @@ void DominanceFrontier::splitBlock(BasicBlock *NewBB) {
          && "NewBB should have a single successor!");
   BasicBlock *NewBBSucc = NewBB->getTerminator()->getSuccessor(0);
 
-  std::vector<BasicBlock*> PredBlocks;
+  SmallVector<BasicBlock*, 8> PredBlocks;
   for (pred_iterator PI = pred_begin(NewBB), PE = pred_end(NewBB);
        PI != PE; ++PI)
       PredBlocks.push_back(*PI);  
@@ -153,7 +153,7 @@ void DominanceFrontier::splitBlock(BasicBlock *NewBB) {
     // Verify whether this block dominates a block in predblocks.  If not, do
     // not update it.
     bool BlockDominatesAny = false;
-    for (std::vector<BasicBlock*>::const_iterator BI = PredBlocks.begin(), 
+    for (SmallVectorImpl<BasicBlock*>::const_iterator BI = PredBlocks.begin(), 
            BE = PredBlocks.end(); BI != BE; ++BI) {
       if (DT.dominates(FI, *BI)) {
         BlockDominatesAny = true;