[all-commits] [llvm/llvm-project] 5a64bc: [DAGCombiner] Remove overzealous assertion when fo...

[Nikita Popov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 5a64bc207ee07d939271ee8631bf28b01e431a46
      https://github.com/llvm/llvm-project/commit/5a64bc207ee07d939271ee8631bf28b01e431a46
  Author: Nikita Popov <npopov at redhat.com>
  Date:   2022-06-07 (Tue, 07 Jun 2022)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    A llvm/test/CodeGen/X86/pr55846.ll

  Log Message:
  -----------
  [DAGCombiner] Remove overzealous assertion when folding assert+trunc+assert (PR55846)

These assert that there are no "useless" assertzext/assertsext nodes
(that assert a wider width than a following trunc), but I don't think
there is anything preventing such nodes from reaching this code.
I don't think the assertion is relevant for correctness of this
transform either -- if such an assert is present, then the other
one will always be to a smaller width, and we'll pick that one.
The assertion dates back to D37017.

Fixes https://github.com/llvm/llvm-project/issues/55846.

Differential Revision: https://reviews.llvm.org/D126952