silence a bogus warning

llvm-svn: 21320
diff --git a/llvm/lib/Transforms/Scalar/CondPropagate.cpp b/llvm/lib/Transforms/Scalar/CondPropagate.cpp
index 138be52..0e63b51 100644
--- a/llvm/lib/Transforms/Scalar/CondPropagate.cpp
+++ b/llvm/lib/Transforms/Scalar/CondPropagate.cpp
@@ -83,7 +83,7 @@
   // See if we can fold any PHI nodes in this block now.
   // FIXME: This would not be required if removePredecessor did this for us!!
   PHINode *PN;
-  for (BasicBlock::iterator I = BB->begin(); PN = dyn_cast<PHINode>(I++); )
+  for (BasicBlock::iterator I = BB->begin(); (PN = dyn_cast<PHINode>(I++)); )
     if (Value *PNV = hasConstantValue(PN))
       if (!isa<Instruction>(PNV)) {
         PN->replaceAllUsesWith(PNV);