InstCombine: Don't try to use aggregate elements of ConstantExprs.

PR18600.

llvm-svn: 200028

1 files changed, 7 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
index 7ffb01b5b2a..8b6a5c0e3f6 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
@@ -25,11 +25,13 @@ static bool CheapToScalarize(Value *V, bool isConstant) {
     if (isConstant) return true;
 
     // If all elts are the same, we can extract it and use any of the values.
-    Constant *Op0 = C->getAggregateElement(0U);
-    for (unsigned i = 1, e = V->getType()->getVectorNumElements(); i != e; ++i)
-      if (C->getAggregateElement(i) != Op0)
-        return false;
-    return true;
+    if (Constant *Op0 = C->getAggregateElement(0U)) {
+      for (unsigned i = 1, e = V->getType()->getVectorNumElements(); i != e;
+           ++i)
+        if (C->getAggregateElement(i) != Op0)
+          return false;
+      return true;
+    }
   }
   Instruction *I = dyn_cast<Instruction>(V);
   if (!I) return false;