[all-commits] [llvm/llvm-project] 1de188: [CodeGen] Fix a scalable-vector crash in VSELECT l...

[Fraser Cormack via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 1de1887f5f18cdd2cffb756afcbfb5274b4fd92f
      https://github.com/llvm/llvm-project/commit/1de1887f5f18cdd2cffb756afcbfb5274b4fd92f
  Author: Fraser Cormack <fraser at codeplay.com>
  Date:   2021-06-03 (Thu, 03 Jun 2021)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
    M llvm/test/CodeGen/RISCV/rvv/vselect-fp-rv32.ll
    M llvm/test/CodeGen/RISCV/rvv/vselect-fp-rv64.ll

  Log Message:
  -----------
  [CodeGen] Fix a scalable-vector crash in VSELECT legalization

The `DAGTypeLegalizer::WidenVSELECTMask` function is not (yet) ready for
scalable vector types, and has numerous places in which it tries to grab
either the fixed size or number of elements of its types.

I believe that it should be possible to update this method to properly
account for scalable-vector types, but we don't have test cases for
that; RISC-V bails out early on as it has legal i1 vector masks. As
such, this patch just prevents it from crashing.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D103536