[all-commits] [llvm/llvm-project] f51477: [DebugInfo][LiveDebugValues] Teach Live Debug Valu...

[Tom Weaver via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: f5147765ba170b4809dc72d34359be3355d48de8
      https://github.com/llvm/llvm-project/commit/f5147765ba170b4809dc72d34359be3355d48de8
  Author: Tom Weaver <Tom.Weaver at Sony.com>
  Date:   2020-01-24 (Fri, 24 Jan 2020)

  Changed paths:
    M llvm/lib/CodeGen/LiveDebugValues.cpp
    M llvm/test/DebugInfo/MIR/X86/entry-value-of-modified-param.mir
    A llvm/test/DebugInfo/MIR/X86/livedebugvalues-ignores-metaInstructions.mir

  Log Message:
  -----------
  [DebugInfo][LiveDebugValues] Teach Live Debug Values About Meta Instructions

Previously LiveDebugValues pass would consider meta instructions that 'fiddle' with liveness of registers as register definitions when transfering register defs. This would mean that, for example, a KILL instruction would cause LiveDebugValues to terminate the range of an earlier DBG_VALUE instruction resulting in the none propogation of said DBG_VALUE instructions into later blocks.

This patch adds the check and a helpful comment, fixes a test that previously tested for the broken behaviour by coincidence and adds a test specifically for this.

reviewers: vsk, dstenb, djtodoro

Differential Revision: https://reviews.llvm.org/D73210