[all-commits] [llvm/llvm-project] fb4aa3: [ExpandMemCmp] Allow overlaping loads in the zero-...

[Clement Courbet via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: fb4aa30f272be7d8af83251a8178851b6e63ecfe
      https://github.com/llvm/llvm-project/commit/fb4aa30f272be7d8af83251a8178851b6e63ecfe
  Author: Clement Courbet <courbet at google.com>
  Date:   2020-04-02 (Thu, 02 Apr 2020)

  Changed paths:
    M llvm/lib/Target/X86/X86TargetTransformInfo.cpp
    M llvm/test/CodeGen/X86/memcmp-more-load-pairs.ll
    M llvm/test/CodeGen/X86/memcmp.ll
    M llvm/test/Transforms/ExpandMemCmp/X86/memcmp.ll

  Log Message:
  -----------
  [ExpandMemCmp] Allow overlaping loads in the zero-relational case.

Summary:
This allows doing `memcmp(p, q, 7)` with 2 loads instead of a call to
memcmp.
This fixes part of PR45147.

Reviewers: spatel

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76133