[all-commits] [llvm/llvm-project] 147cfc: [X86] LowerShiftByScalarVariable - find splat patt...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 147cfcbef1255ba2b4875b76708dab1a685085f5
      https://github.com/llvm/llvm-project/commit/147cfcbef1255ba2b4875b76708dab1a685085f5
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2022-03-04 (Fri, 04 Mar 2022)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/pr15296.ll
    M llvm/test/CodeGen/X86/vector-fshl-128.ll
    M llvm/test/CodeGen/X86/vector-fshl-256.ll
    M llvm/test/CodeGen/X86/vector-fshl-512.ll
    M llvm/test/CodeGen/X86/vector-fshl-rot-128.ll
    M llvm/test/CodeGen/X86/vector-fshl-rot-256.ll
    M llvm/test/CodeGen/X86/vector-fshl-rot-512.ll
    M llvm/test/CodeGen/X86/vector-fshr-128.ll
    M llvm/test/CodeGen/X86/vector-fshr-256.ll
    M llvm/test/CodeGen/X86/vector-fshr-512.ll
    M llvm/test/CodeGen/X86/vector-fshr-rot-128.ll
    M llvm/test/CodeGen/X86/vector-fshr-rot-256.ll
    M llvm/test/CodeGen/X86/vector-fshr-rot-512.ll
    M llvm/test/CodeGen/X86/vector-rotate-128.ll
    M llvm/test/CodeGen/X86/vector-rotate-256.ll
    M llvm/test/CodeGen/X86/vector-rotate-512.ll
    M llvm/test/CodeGen/X86/vector-shift-ashr-128.ll
    M llvm/test/CodeGen/X86/vector-shift-ashr-256.ll
    M llvm/test/CodeGen/X86/vector-shift-ashr-512.ll
    M llvm/test/CodeGen/X86/vector-shift-lshr-128.ll
    M llvm/test/CodeGen/X86/vector-shift-lshr-256.ll
    M llvm/test/CodeGen/X86/vector-shift-lshr-512.ll
    M llvm/test/CodeGen/X86/vector-shift-shl-128.ll
    M llvm/test/CodeGen/X86/vector-shift-shl-256.ll
    M llvm/test/CodeGen/X86/vector-shift-shl-512.ll
    M llvm/test/CodeGen/X86/vselect-avx.ll

  Log Message:
  -----------
  [X86] LowerShiftByScalarVariable - find splat patterns with getSplatSourceVector instead of getSplatValue

This completes the removal of uses of SelectionDAG::getSplatValue started in D119090 - by avoiding extracting the splatted element we make it a lot easier to zero-extend the bottom 64-bits of the shift amount and fixes issues we had on 32-bit targets where i64 isn't legal.

I've removed the old version of getTargetVShiftNode that took the scalar shift amount argument and LowerRotate can finally efficiently handle vXi16 rotates-by-scalar (using the same code as general funnel-shifts).

The only regression we see is in the X86-AVX2 PR52719 test case in vector-shift-ashr-256.ll - this is now hitting the same problem as the X86-AVX1 case (failure to simplify a multi-use X86ISD::VBROADCAST_LOAD) which I intend to address in a follow up patch.