[all-commits] [llvm/llvm-project] 3a503c: [X86] Reduce the number of emitted fragments due t...

[KanRobert via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 3a503ce66318ed65d071f6401af5750640d33444
      https://github.com/llvm/llvm-project/commit/3a503ce66318ed65d071f6401af5750640d33444
  Author: Shengchen Kan <shengchen.kan at intel.com>
  Date:   2020-03-12 (Thu, 12 Mar 2020)

  Changed paths:
    M llvm/include/llvm/MC/MCFragment.h
    M llvm/lib/MC/MCAssembler.cpp
    M llvm/lib/MC/MCFragment.cpp
    M llvm/lib/MC/MCObjectStreamer.cpp
    M llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
    M llvm/test/MC/X86/align-branch-64-negative.s

  Log Message:
  -----------
  [X86] Reduce the number of emitted fragments due to branch align

Summary:
Currently, a BoundaryAlign fragment may be inserted after the branch
that needs to be aligned to truncate the current fragment, this fragment is
unused at most of time. To avoid that, we can insert a new empty Data
fragment instead. Non-relaxable instruction is usually emitted into Data
fragment, so the inserted empty Data fragment will be reused at a high
possibility.

Reviewers: annita.zhang, reames, MaskRay, craig.topper, LuoYuanke, jyknight

Reviewed By: reames, LuoYuanke

Subscribers: llvm-commits, dexonsmith, hiraditya

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75438