[all-commits] [llvm/llvm-project] 8d75df: [RDA] Don't adjust ReachingDefDefaultVal (NFCI)

[Nikita Popov via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 8d75df14389bddc4a546cf059d223e730539bc53
      https://github.com/llvm/llvm-project/commit/8d75df14389bddc4a546cf059d223e730539bc53
  Author: Nikita Popov <nikita.ppv at gmail.com>
  Date:   2020-04-06 (Mon, 06 Apr 2020)

  Changed paths:
    M llvm/lib/CodeGen/ReachingDefAnalysis.cpp

  Log Message:
  -----------
  [RDA] Don't adjust ReachingDefDefaultVal (NFCI)

At the end of a basic block, RDA adjusts all the reaching defs it
found to be relative to the end of the basic block, rather than the
start of it. However, it also does this to registers which don't
have a reaching def, indicated by ReachingDefDefaultVal. This means
that code checking against ReachingDefDefaultVal will not skip them,
and may insert them into the reaching definition list. This is
ultimately harmless, but causes unnecessary work and is logically
not right.

Differential Revision: https://reviews.llvm.org/D77506