[all-commits] [llvm/llvm-project] 46329f: [ImplicitNullCheck] Handle instructions that prese...

[annamthomas via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 46329f6079da99133eab7942e79226b2afb40e75
      https://github.com/llvm/llvm-project/commit/46329f6079da99133eab7942e79226b2afb40e75
  Author: Anna Thomas <anna at azul.com>
  Date:   2020-09-10 (Thu, 10 Sep 2020)

  Changed paths:
    M llvm/include/llvm/CodeGen/TargetInstrInfo.h
    M llvm/lib/CodeGen/ImplicitNullChecks.cpp
    M llvm/lib/Target/X86/X86InstrInfo.cpp
    M llvm/lib/Target/X86/X86InstrInfo.h
    M llvm/test/CodeGen/X86/implicit-null-check-negative.ll
    M llvm/test/CodeGen/X86/implicit-null-check.ll

  Log Message:
  -----------
  [ImplicitNullCheck] Handle instructions that preserve zero value

This is the first in a series of patches to make implicit null checks
more general. This patch identifies instructions that preserves zero
value of a register and considers that as a valid instruction to hoist
along with the faulting load. See added testcases.

Reviewed-By: reames, dantrushin

Differential Revision: https://reviews.llvm.org/D87108