[all-commits] [llvm/llvm-project] 754f3a: [ValueTracking][InstCombine] Add a new API to allo...

[luxufan via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 754f3ae65518331b7175d7a9b4a124523ebe6eac
      https://github.com/llvm/llvm-project/commit/754f3ae65518331b7175d7a9b4a124523ebe6eac
  Author: luxufan <luxufan at iscas.ac.cn>
  Date:   2023-05-19 (Fri, 19 May 2023)

  Changed paths:
    M llvm/include/llvm/Analysis/ValueTracking.h
    M llvm/lib/Analysis/ValueTracking.cpp
    M llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
    M llvm/test/Transforms/InstCombine/ispow2.ll
    M llvm/test/Transforms/InstCombine/prevent-cmp-merge.ll

  Log Message:
  -----------
  [ValueTracking][InstCombine] Add a new API to allow to ignore poison generating flags or metadatas when implying poison

This patch add a new API `impliesPoisonIgnoreFlagsOrMetadatas` which is
the same as `impliesPoison` but ignoring poison generating flags or
metadatas in the process of implying poison and recording these ignored
instructions.

In InstCombineSelect, replacing `impliesPoison` with
`impliesPoisonIgnoreFlagsOrMetadatas` to allow more patterns like
`select i1 %a, i1 %b, i1 false` to be optimized to and/or instructions
by droping the poison generating flags or metadatas.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D149404