[all-commits] [llvm/llvm-project] cd8333: [PowerPC] Fold redundant load immediates of zero a...

[Kamau Bridgeman via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: cd83333fc8fa3d2924087485bc3d1998665b4987
      https://github.com/llvm/llvm-project/commit/cd83333fc8fa3d2924087485bc3d1998665b4987
  Author: Kamau Bridgeman <kamau.bridgeman at ibm.com>
  Date:   2020-05-12 (Tue, 12 May 2020)

  Changed paths:
    M llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
    M llvm/lib/Target/PowerPC/PPCInstrInfo.h
    M llvm/lib/Target/PowerPC/PPCMIPeephole.cpp
    M llvm/test/CodeGen/PowerPC/convert-rr-to-ri-instrs.mir
    A llvm/test/CodeGen/PowerPC/fold-remove-li.ll
    M llvm/test/CodeGen/PowerPC/save-crbp-ppc32svr4.ll

  Log Message:
  -----------
  [PowerPC] Fold redundant load immediates of zero and delete if possible

This patch folds redundant load immediates into a zero for instructions
which recognise this as the value zero and not the register. If the load
immediate is no longer in use it is then deleted.

This is already done in earlier passes but the ppc-mi-peephole allows for
a more general implementation.

Differential Revision: https://reviews.llvm.org/D69168