[all-commits] [llvm/llvm-project] 3638bd: [ConstantFold] Handle undef/poison when constant f...

[Björn Pettersson via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 3638bdfbda01e5a4f17c330edc602e413359c722
      https://github.com/llvm/llvm-project/commit/3638bdfbda01e5a4f17c330edc602e413359c722
  Author: Bjorn Pettersson <bjorn.a.pettersson at ericsson.com>
  Date:   2021-03-12 (Fri, 12 Mar 2021)

  Changed paths:
    M llvm/lib/Analysis/ConstantFolding.cpp
    M llvm/test/Transforms/InstSimplify/ConstProp/smul-fix-sat.ll
    M llvm/test/Transforms/InstSimplify/ConstProp/smul-fix.ll

  Log Message:
  -----------
  [ConstantFold] Handle undef/poison when constant folding smul_fix/smul_fix_sat

Do constant folding according to
  posion * C -> poison
  C * poison -> poison
  undef * C -> 0
  C * undef -> 0
for smul_fix and smul_fix_sat intrinsics (for any scale).

Reviewed By: nikic, aqjune, nagisa

Differential Revision: https://reviews.llvm.org/D98410


  Commit: 529c8e8dc6e9826b298b5e8586d55940abfee0ba
      https://github.com/llvm/llvm-project/commit/529c8e8dc6e9826b298b5e8586d55940abfee0ba
  Author: Bjorn Pettersson <bjorn.a.pettersson at ericsson.com>
  Date:   2021-03-12 (Fri, 12 Mar 2021)

  Changed paths:
    M llvm/lib/Analysis/InstructionSimplify.cpp
    A llvm/test/Transforms/InstSimplify/smul_fix.ll

  Log Message:
  -----------
  [InstSimplify] Simplify smul.fix and smul.fix.sat

Add simplification of smul.fix and smul.fix.sat according to
  X * 0 -> 0
  X * undef -> 0
  X * (1 << scale) -> X

This includes the commuted patterns and splatted vectors.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D98299


Compare: https://github.com/llvm/llvm-project/compare/849f8183fb99...529c8e8dc6e9