[PATCH] D13466: [AArch64] Implement vector splitting on UADDV.

[Jun Bum Lim via llvm-commits]

junbuml added a comment.

Please also see below simple test case for <16xi32> smaxv :

  define i32 @foo(<16 x i32>* nocapture readonly %arr)  {
    %arr.load = load <16 x i32>, <16 x i32>* %arr
    %rdx.shuf = shufflevector <16 x i32> %arr.load, <16 x i32> undef, <16 x i32> <i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
    %rdx.minmax.cmp22 = icmp sgt <16 x i32> %arr.load, %rdx.shuf
    %rdx.minmax.select23 = select <16 x i1> %rdx.minmax.cmp22, <16 x i32> %arr.load, <16 x i32> %rdx.shuf
    %rdx.shuf24 = shufflevector <16 x i32> %rdx.minmax.select23, <16 x i32> undef, <16 x i32> <i32 4, i32 5, i32 6, i32 7, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
    %rdx.minmax.cmp25 = icmp sgt <16 x i32> %rdx.minmax.select23, %rdx.shuf24
    %rdx.minmax.select26 = select <16 x i1> %rdx.minmax.cmp25, <16 x i32> %rdx.minmax.select23, <16 x i32> %rdx.shuf24
    %rdx.shuf27 = shufflevector <16 x i32> %rdx.minmax.select26, <16 x i32> undef, <16 x i32> <i32 2, i32 3, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
    %rdx.minmax.cmp28 = icmp sgt <16 x i32> %rdx.minmax.select26, %rdx.shuf27
    %rdx.minmax.select29 = select <16 x i1> %rdx.minmax.cmp28, <16 x i32> %rdx.minmax.select26, <16 x i32> %rdx.shuf27
    %rdx.shuf30 = shufflevector <16 x i32> %rdx.minmax.select29, <16 x i32> undef, <16 x i32> <i32 1, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
    %rdx.minmax.cmp31 = icmp sgt <16 x i32> %rdx.minmax.select29, %rdx.shuf30
    %rdx.minmax.cmp31.elt = extractelement <16 x i1> %rdx.minmax.cmp31, i32 0
    %rdx.minmax.select29.elt = extractelement <16 x i32> %rdx.minmax.select29, i32 0
    %rdx.shuf30.elt = extractelement <16 x i32> %rdx.minmax.select29, i32 1
    %r = select i1 %rdx.minmax.cmp31.elt, i32 %rdx.minmax.select29.elt, i32 %rdx.shuf30.elt
    ret i32 %r
  }


http://reviews.llvm.org/D13466