[PATCH] D53823: [X86] In lowerVectorShuffleAsBroadcast, make peeking through CONCAT_VECTORS work correctly if we already walked through a bitcast that changed the element size.

[Craig Topper via Phabricator via llvm-commits]

craig.topper added a comment.

Here's a test case that crashes with -mattr=avx2

  define <8 x float> @foo(<4 x float> %x, <4 x float> %y, float %z) {
  entry:
    %tmp = shufflevector <4 x float> %x, <4 x float> %y, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
    %bc = bitcast <8 x float> %tmp to <4 x i64>
    %tmp1 = extractelement <4 x i64> %bc, i32 3
    %tmp2 = bitcast i64 %tmp1 to <2 x float>
    %tmp4 = extractelement <2 x float> %tmp2, i32 1
    %tmp5 = insertelement <8 x float> undef, float %tmp4, i32 4
    %tmp6 = insertelement <8 x float> %tmp5, float %z, i32 5
    ret <8 x float> %tmp6
  }


https://reviews.llvm.org/D53823