[all-commits] [llvm/llvm-project] 1993f9: [ValueTracking][SVE] Fix getOffsetFromIndex for sc...

[huihzhang via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 1993f95f2b1eb2d8da7f1a01e977d8fe06314bcf
      https://github.com/llvm/llvm-project/commit/1993f95f2b1eb2d8da7f1a01e977d8fe06314bcf
  Author: Huihui Zhang <huihuiz at quicinc.com>
  Date:   2020-03-20 (Fri, 20 Mar 2020)

  Changed paths:
    M llvm/lib/Analysis/ValueTracking.cpp
    A llvm/test/Transforms/MemCpyOpt/vscale-memset.ll

  Log Message:
  -----------
  [ValueTracking][SVE] Fix getOffsetFromIndex for scalable vector.

Summary:
Return None if GEP index type is scalable vector. Size of scalable vectors
are multiplied by a runtime constant.

Avoid transforming:
  %a = bitcast i8* %p to <vscale x 16 x i8>*
  %tmp0 = getelementptr <vscale x 16 x i8>, <vscale x 16 x i8>* %a, i64 0
  store <vscale x 16 x i8> zeroinitializer, <vscale x 16 x i8>* %tmp0
  %tmp1 = getelementptr <vscale x 16 x i8>, <vscale x 16 x i8>* %a, i64 1
  store <vscale x 16 x i8> zeroinitializer, <vscale x 16 x i8>* %tmp1

into:
  %a = bitcast i8* %p to <vscale x 16 x i8>*
  %tmp0 = getelementptr <vscale x 16 x i8>, <vscale x 16 x i8>* %a, i64 0
  %1 = bitcast <vscale x 16 x i8>* %tmp0 to i8*
  call void @llvm.memset.p0i8.i64(i8* align 16 %1, i8 0, i64 32, i1 false)

Reviewers: sdesmalen, efriedma, apazos, reames

Reviewed By: sdesmalen

Subscribers: tschuett, hiraditya, rkruppe, arphaman, psnobl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76464