[all-commits] [llvm/llvm-project] 9bda1d: [TwoAddressInstruction] Propagate undef flags for ...

[Carl Ritson via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 9bda1de0b6096d26e87fed18cb681cc3e5b8319a
      https://github.com/llvm/llvm-project/commit/9bda1de0b6096d26e87fed18cb681cc3e5b8319a
  Author: Carl Ritson <carl.ritson at amd.com>
  Date:   2024-02-07 (Wed, 07 Feb 2024)

  Changed paths:
    M llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
    A llvm/test/CodeGen/AMDGPU/GlobalISel/twoaddr-extract-dyn-v7f64.mir

  Log Message:
  -----------
  [TwoAddressInstruction] Propagate undef flags for partial defs (#79286)

If part of a register (lowered from REG_SEQUENCE) is undefined then we
should propagate undef flags to uses of those lanes. This is only
performed when live intervals are present as it requires live intervals
to correctly match uses to defs, and the primary goal is to allow
precise computation of subrange intervals.