[InstCombine] Don't crash on out of bounds index in the insertelement

Differential Revision: https://reviews.llvm.org/D40390

llvm-svn: 320049

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
index 6c99007475c..65a96b96522 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
@@ -781,6 +781,10 @@ Instruction *InstCombiner::visitInsertElementInst(InsertElementInst &IE) {
   Value *ScalarOp = IE.getOperand(1);
   Value *IdxOp    = IE.getOperand(2);
 
+  if (auto *V = SimplifyInsertElementInst(
+          VecOp, ScalarOp, IdxOp, SQ.getWithInstruction(&IE)))
+    return replaceInstUsesWith(IE, V);
+
   // Inserting an undef or into an undefined place, remove this.
   if (isa<UndefValue>(ScalarOp) || isa<UndefValue>(IdxOp))
     replaceInstUsesWith(IE, VecOp);