[all-commits] [llvm/llvm-project] 3cf4ab: [AArch64] Add an option to reserve physical regist...

[weiguozhi via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 3cf4ab54476e549a787b1240a4fd2e9576822f17
      https://github.com/llvm/llvm-project/commit/3cf4ab54476e549a787b1240a4fd2e9576822f17
  Author: Guozhi Wei <carrot at google.com>
  Date:   2022-09-06 (Tue, 06 Sep 2022)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp
    M llvm/lib/Target/AArch64/AArch64RegisterInfo.h
    M llvm/lib/Target/AArch64/AArch64Subtarget.cpp
    M llvm/lib/Target/AArch64/AArch64Subtarget.h
    M llvm/test/CodeGen/AArch64/arm64-platform-reg.ll

  Log Message:
  -----------
  [AArch64] Add an option to reserve physical registers from RA

This patch adds an option --reserve-regs-for-regalloc, so we can reserve a list
of physical registers. These registers will not be used by register allocator,
but can still be used as ABI requests such as passing arguments to function
call.

Its main purpose is simulating high register pressure by reserving many physical
registers. So it will be much easier to test and debug register allocation
changes.

Differential Revision: https://reviews.llvm.org/D132717