[all-commits] [llvm/llvm-project] f0b3b6: [DAG] isConstantIntBuildVectorOrConstantInt - peek...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: f0b3b6d15b2c0ee2cff2dd31dc075adb5d9a4ff7
      https://github.com/llvm/llvm-project/commit/f0b3b6d15b2c0ee2cff2dd31dc075adb5d9a4ff7
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2024-10-20 (Sun, 20 Oct 2024)

  Changed paths:
    M llvm/include/llvm/CodeGen/SelectionDAG.h
    M llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
    M llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/avx2-arith.ll
    M llvm/test/CodeGen/X86/combine-sra.ll
    M llvm/test/CodeGen/X86/midpoint-int-vec-128.ll
    M llvm/test/CodeGen/X86/midpoint-int-vec-256.ll
    M llvm/test/CodeGen/X86/min-legal-vector-width.ll
    M llvm/test/CodeGen/X86/pmul.ll
    M llvm/test/CodeGen/X86/prefer-avx256-wide-mul.ll
    M llvm/test/CodeGen/X86/psubus.ll
    M llvm/test/CodeGen/X86/sat-add.ll
    M llvm/test/CodeGen/X86/vector-shuffle-combining-sse41.ll
    M llvm/test/CodeGen/X86/vector-trunc-packus.ll
    M llvm/test/CodeGen/X86/vector-trunc-ssat.ll
    M llvm/test/CodeGen/X86/vector-trunc-usat.ll

  Log Message:
  -----------
  [DAG] isConstantIntBuildVectorOrConstantInt - peek through bitcasts (#112710) (REAPPLIED)

Alter both isConstantIntBuildVectorOrConstantInt + isConstantFPBuildVectorOrConstantFP to return a bool instead of the underlying SDNode, and adjust usage to account for this.

Update isConstantIntBuildVectorOrConstantInt to peek though bitcasts when attempting to find a constant, in particular this improves canonicalization of constants to the RHS on commutable instructions.

X86 is the beneficiary here as it often bitcasts rematerializable 0/-1 vector constants as vXi32 and bitcasts to the requested type

Minor cleanup that helps with #107423

Reapplied after regression fix ba1255def64a9c3c68d97ace051eec76f546eeb0



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