Check to see if a two-entry PHI block can be simplified

before trying to merge the block into its predecessors.
This allows two-entry-phi-return.ll to be simplified
into a single basic block.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48252 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 6 deletions

diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index ac5c2ec770..b9a20c113f 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1224,6 +1224,12 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
   // away...
   Changed |= ConstantFoldTerminator(BB);
 
+  // If there is a trivial two-entry PHI node in this basic block, and we can
+  // eliminate it, do so now.
+  if (PHINode *PN = dyn_cast<PHINode>(BB->begin()))
+    if (PN->getNumIncomingValues() == 2)
+      Changed |= FoldTwoEntryPHINode(PN); 
+
   // If this is a returning block with only PHI nodes in it, fold the return
   // instruction into any unconditional branch predecessors.
   //
@@ -1915,11 +1921,5 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
         }
       }
 
-  // If there is a trivial two-entry PHI node in this basic block, and we can
-  // eliminate it, do so now.
-  if (PHINode *PN = dyn_cast<PHINode>(BB->begin()))
-    if (PN->getNumIncomingValues() == 2)
-      Changed |= FoldTwoEntryPHINode(PN); 
-
   return Changed;
 }