[all-commits] [llvm/llvm-project] 219767: AArch64: Relax x16/x17 constraint on AUT in certai...

[Peter Collingbourne via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 2197671109815ed42661fadf5d38f9e510d310c6
      https://github.com/llvm/llvm-project/commit/2197671109815ed42661fadf5d38f9e510d310c6
  Author: Peter Collingbourne <pcc at google.com>
  Date:   2025-07-09 (Wed, 09 Jul 2025)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
    M llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
    M llvm/lib/Target/AArch64/AArch64InstrInfo.td
    M llvm/lib/Target/AArch64/AArch64Subtarget.cpp
    M llvm/lib/Target/AArch64/AArch64Subtarget.h
    M llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
    M llvm/test/CodeGen/AArch64/ptrauth-call.ll
    M llvm/test/CodeGen/AArch64/ptrauth-fpac.ll
    M llvm/test/CodeGen/AArch64/ptrauth-intrinsic-auth-resign-with-blend.ll
    M llvm/test/CodeGen/AArch64/ptrauth-intrinsic-auth-resign.ll

  Log Message:
  -----------
  AArch64: Relax x16/x17 constraint on AUT in certain cases.

On most operating systems, the x16 and x17 registers are not special,
so there is no benefit, and only a code size cost, to constraining AUT to
only using them. Therefore, adjust the backend to only use the AUT pseudo
(renamed AUTx16x17 for clarity) on Darwin platforms. All other platforms
use an unconstrained variant of the pseudo, AUTxMxN, for selection.

Reviewers: ahmedbougacha, kovdan01, atrosinenko

Reviewed By: atrosinenko

Pull Request: https://github.com/llvm/llvm-project/pull/132857



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