When determining the new index for an insertelement, we may not assume that an

index greater than the size of the vector is invalid. The shuffle may be
shrinking the size of the vector. Fixes a crash!

Also drop the maximum recursion depth of the safety check for this
optimization to five.

llvm-svn: 183080

1 files changed, 11 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/vec_shuffle.ll b/llvm/test/Transforms/InstCombine/vec_shuffle.ll
index 4b7a049baec..5ffe6c04372 100644
--- a/llvm/test/Transforms/InstCombine/vec_shuffle.ll
+++ b/llvm/test/Transforms/InstCombine/vec_shuffle.ll
@@ -174,3 +174,14 @@ define <2 x i8> @test13b(i8 %x) {
   %B = shufflevector <2 x i8> %A, <2 x i8> undef, <2 x i32> <i32 undef, i32 0>
   ret <2 x i8> %B
 }
+
+define <2 x i8> @test13c(i8 %x1, i8 %x2) {
+; CHECK: @test13c
+; CHECK-NEXT: insertelement <2 x i8> {{.*}}, i32 0
+; CHECK-NEXT: insertelement <2 x i8> {{.*}}, i32 1
+; CHECK-NEXT: ret
+  %A = insertelement <4 x i8> undef, i8 %x1, i32 0
+  %B = insertelement <4 x i8> %A, i8 %x2, i32 2
+  %C = shufflevector <4 x i8> %B, <4 x i8> undef, <2 x i32> <i32 0, i32 2>
+  ret <2 x i8> %C
+}