[all-commits] [llvm/llvm-project] 6cb395: [X86AsmBackend] Be consistent about placing defini...

[Philip Reames via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 6cb3957730e9085bb7c37d871c790f910efdd6a7
      https://github.com/llvm/llvm-project/commit/6cb3957730e9085bb7c37d871c790f910efdd6a7
  Author: Philip Reames <listmail at philipreames.com>
  Date:   2020-01-11 (Sat, 11 Jan 2020)

  Changed paths:
    M llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp

  Log Message:
  -----------
  [X86AsmBackend] Be consistent about placing definitions out of line [NFC]


  Commit: 563d3e344452c8923db09b043b8db471fc413b1e
      https://github.com/llvm/llvm-project/commit/563d3e344452c8923db09b043b8db471fc413b1e
  Author: Philip Reames <listmail at philipreames.com>
  Date:   2020-01-11 (Sat, 11 Jan 2020)

  Changed paths:
    M llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp

  Log Message:
  -----------
  [X86AsmBackend] Move static function before sole use [NFC]


  Commit: 1d641daf260308815d014d1bf1b424a1ed1e7277
      https://github.com/llvm/llvm-project/commit/1d641daf260308815d014d1bf1b424a1ed1e7277
  Author: Philip Reames <listmail at philipreames.com>
  Date:   2020-01-11 (Sat, 11 Jan 2020)

  Changed paths:
    M llvm/lib/Target/X86/X86MCInstLower.cpp
    M llvm/test/CodeGen/X86/align-branch-boundary-suppressions.ll
    M llvm/test/CodeGen/X86/stackmap-nops.ll
    M llvm/test/MC/X86/stackmap-nops.ll

  Log Message:
  -----------
  [X86] Adjust nop emission by compiler to consider target decode limitations

The primary motivation of this change is to bring the code more closely in sync behavior wise with the assembler's version of nop emission.  I'd like to eventually factor them into one, but that's hard to do when one has features the other doesn't.

The longest encodeable nop on x86 is 15 bytes, but many processors - for instance all intel chips - can't decode the 15 byte form efficiently.  On those processors, it's better to use either a 10 byte or 11 byte sequence depending.


Compare: https://github.com/llvm/llvm-project/compare/fce887beb797...1d641daf2603