[all-commits] [llvm/llvm-project] 62e608: [RISCV] Implement shouldTransformSignedTruncationC...

[Craig Topper via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 62e6082dcc7a7ce22fb98f9a0fd98a0385001437
      https://github.com/llvm/llvm-project/commit/62e6082dcc7a7ce22fb98f9a0fd98a0385001437
  Author: Craig Topper <craig.topper at sifive.com>
  Date:   2023-05-08 (Mon, 08 May 2023)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/lib/Target/RISCV/RISCVISelLowering.h
    M llvm/test/CodeGen/RISCV/lack-of-signed-truncation-check.ll
    M llvm/test/CodeGen/RISCV/signed-truncation-check.ll

  Log Message:
  -----------
  [RISCV] Implement shouldTransformSignedTruncationCheck.

This helps avoid constant materialization for the patterns
InstCombine emits for something like INT_MIN <= X && x <= INT_MAX.

See top of changed test files for more detailed explanation.

I've enabled this for i16 when Zbb is enabled. sext.b did not seem
to be a benefit due to the constants folding into addi/sltiu.

This an alternative to https://reviews.llvm.org/D149814

Reviewed By: reames

Differential Revision: https://reviews.llvm.org/D149977