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
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index ac5c2ec..b9a20c1 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1224,6 +1224,12 @@
// 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 @@
}
}
- // 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;
}