[all-commits] [llvm/llvm-project] 9b9945: [SCCP] Only handle unknown lattice values in resol...

[Nikita Popov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 9b994593cc2aec4c4979400ec747965bd3823bc0
      https://github.com/llvm/llvm-project/commit/9b994593cc2aec4c4979400ec747965bd3823bc0
  Author: Nikita Popov <npopov at redhat.com>
  Date:   2022-07-01 (Fri, 01 Jul 2022)

  Changed paths:
    M llvm/lib/Transforms/Utils/SCCPSolver.cpp
    M llvm/test/Transforms/SCCP/PR26044.ll
    M llvm/test/Transforms/SCCP/ipsccp-phi-one-pred-dead.ll

  Log Message:
  -----------
  [SCCP] Only handle unknown lattice values in resolvedUndefsIn()

This is a minor refinement of resolvedUndefsIn(), mostly for clarity.
If the value of an instruction is undef, then that's already a legal
final result -- we can safely rauw such an instruction with undef.
We only need to mark unknown values as overdefined, as that's the
result we get for an instruction that has not been processed because
it has an undef operand.

Differential Revision: https://reviews.llvm.org/D128251