[all-commits] [llvm/llvm-project] 4ef91f: [DAGCombiner] Don't speculatively create an all on...

[Craig Topper via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 4ef91f5871a3c38bb2324f89b47a2a845e8a33fd
      https://github.com/llvm/llvm-project/commit/4ef91f5871a3c38bb2324f89b47a2a845e8a33fd
  Author: Craig Topper <craig.topper at sifive.com>
  Date:   2021-01-05 (Tue, 05 Jan 2021)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

  Log Message:
  -----------
  [DAGCombiner] Don't speculatively create an all ones constant in visitREM that might not be used.

This looks to have been done to save some duplicated code under
two different if statements, but it ends up being harmful to D94073.
This speculative constant can be called on a scalable vector type
with i64 element size when i64 scalars aren't legal. The code tries
and fails to find a vector type with i32 elements that it can use.

So only create the node when we know it will be used.