[all-commits] [llvm/llvm-project] 97ddf4: [DebugInfo][InstrRef] Recover stack-slot tracking ...

[Jeremy Morse via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 97ddf49e43f4dd9cf12242ac36f8c831aba76574
      https://github.com/llvm/llvm-project/commit/97ddf49e43f4dd9cf12242ac36f8c831aba76574
  Author: Jeremy Morse <jeremy.morse at sony.com>
  Date:   2021-10-25 (Mon, 25 Oct 2021)

  Changed paths:
    M llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
    M llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h
    M llvm/unittests/CodeGen/InstrRefLDVTest.cpp

  Log Message:
  -----------
  [DebugInfo][InstrRef] Recover stack-slot tracking performance

This patch is like D111627 -- instead of calculating IDF for every location
on the stack, only do it for the smallest units of interference, and copy
the PHIs for those units to any aliases.

The test added runs placeMLocPHIs directly, and tests that:
 * A def of the lower 8 bits of a stack slot causes all aliasing regs to
   have PHIs placed,
 * It doesn't cause the equivalent location to x86's $ah, which isn't
   aliased, to have a PHI placed.

Differential Revision: https://reviews.llvm.org/D112324