[llvm] [VectorCombine] Use InstSimplifyFolder to simplify instrs on creation. (PR #146350)

[Ramkumar Ramachandra via llvm-commits]

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@@ -48,8 +48,7 @@ define <4 x float> @ext2_v4f32(<4 x float> %x, <4 x float> %y) {
 define <4 x float> @ext2_v2f32v4f32(<2 x float> %x, <4 x float> %y) {
 ; CHECK-LABEL: @ext2_v2f32v4f32(
 ; CHECK-NEXT:    [[TMP1:%.*]] = fneg <2 x float> [[X:%.*]]
-; CHECK-NEXT:    [[TMP2:%.*]] = shufflevector <2 x float> [[TMP1]], <2 x float> poison, <4 x i32> <i32 poison, i32 poison, i32 2, i32 poison>
-; CHECK-NEXT:    [[R:%.*]] = shufflevector <4 x float> [[Y:%.*]], <4 x float> [[TMP2]], <4 x i32> <i32 0, i32 1, i32 6, i32 3>
+; CHECK-NEXT:    [[R:%.*]] = shufflevector <4 x float> [[Y:%.*]], <4 x float> <float undef, float undef, float poison, float undef>, <4 x i32> <i32 0, i32 1, i32 6, i32 3>
 ; CHECK-NEXT:    ret <4 x float> [[R]]
 ;
   %e = extractelement <2 x float> %x, i32 2
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artagnon wrote:

Right, the undef-deprecator warned about this.

https://github.com/llvm/llvm-project/pull/146350