[all-commits] [llvm/llvm-project] db0e65: DAG: Fix broken lowering of is.fplcass fcZero with...

[Matt Arsenault via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: db0e6591612b53910a1b366863348bdb9d7d2fb1
      https://github.com/llvm/llvm-project/commit/db0e6591612b53910a1b366863348bdb9d7d2fb1
  Author: Matt Arsenault <Matthew.Arsenault at amd.com>
  Date:   2023-02-05 (Sun, 05 Feb 2023)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
    M llvm/test/CodeGen/X86/is_fpclass.ll

  Log Message:
  -----------
  DAG: Fix broken lowering of is.fplcass fcZero with DAZ

is.fpclass x, fcZero is not equivalent to fcmp with 0 if
denormals are treated as 0. It would be equivalent to fcZero|fcSubnormal
which can be done separately; this is the minimal correctness fix.

The same optimization was not ported to the GlobalISel version.