[all-commits] [llvm/llvm-project] dfa2ad: [X86] getTargetVShiftNode - remove shift-by-consta...

Simon Pilgrim via All-commits all-commits at lists.llvm.org
Tue Dec 21 05:17:26 PST 2021

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: dfa2ad1ad858a44d7d73de1b042fbe78256b74f7
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2021-12-21 (Tue, 21 Dec 2021)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp

  Log Message:
  [X86] getTargetVShiftNode - remove shift-by-constant handling.

Move shift-by-constant handling and move it into its only user (VSHIFT intrinsics lowering).

This is some prep-work for getTargetVShiftNode to no longer take a scalar shift amount - we're introducing temporary ISD::EXTRACT_VECTOR_ELT nodes via SelectionDAG::getSplatValue to accommodate this which can cause various issues, including unnecessary scalarization and xmm->gpr->xmm transfers, and causes problems for 32-bit codegen if we fail to remove an (illegal) i64 scalar extracted from a (legal) vXi64 vector.

More information about the All-commits mailing list