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

PR18600.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200028 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstCombineVectorOps.cpp b/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
index 7ffb01b5b2a4c24c368bc3300954d65237de4cc2..8b6a5c0e3f6827980b996d33a9a8c6a40961a17c 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
+++ b/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;

diff --git a/test/Transforms/InstCombine/vec_extract_var_elt.ll b/test/Transforms/InstCombine/vec_extract_var_elt.ll
index 3c982873e288195667d6028eb10efe82d95f5320..f6f9e0134a163809ae8dc372275487ec77e5c582 100644 (file)
--- a/test/Transforms/InstCombine/vec_extract_var_elt.ll
+++ b/test/Transforms/InstCombine/vec_extract_var_elt.ll
@@ -16,3 +16,11 @@ define void @test (float %b, <8 x float> * %p)  {
   ret void    
 }
 
+; PR18600
+define i32 @test2(i32 %i) {
+  %e = extractelement <4 x i32> bitcast (<2 x i64> <i64 1, i64 2> to <4 x i32>), i32 %i
+  ret i32 %e
+
+; CHECK-LABEL: @test2
+; CHECK: extractelement
+}