[all-commits] [llvm/llvm-project] e1f140: [RISCV] Delete dead elideCopy code in InsertVSETVL...

[Philip Reames via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e1f1407beb842386b2a414f12be8cf73b85d41bb
      https://github.com/llvm/llvm-project/commit/e1f1407beb842386b2a414f12be8cf73b85d41bb
  Author: Philip Reames <preames at rivosinc.com>
  Date:   2022-06-17 (Fri, 17 Jun 2022)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp

  Log Message:
  -----------
  [RISCV] Delete dead elideCopy code in InsertVSETVLI [nfc]

This code should be dead. A simple whole register copy of an IMPLICIT_DEF, is simply an IMPLICIT_DEF of it's own. (This would not be true for freeze, but is for copy.)  If we find a case which gets here with vector operand copy of an IMPLICIT_DEF, we most likely have an earlier missed optimization anyways.  (The most recent case of this was e6c7a3a, found by Craig during review of this patch.)  There might be others, and if so, we'll revisit them individually as regressions are reported.

Differential Revision: https://reviews.llvm.org/D127996