[all-commits] [llvm/llvm-project] ea9d63: Fix reordering of instructions during VirtRegRewri...

[Carl Ritson via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: ea9d6392f4a375b5183be02ac93eb3a75c169360
      https://github.com/llvm/llvm-project/commit/ea9d6392f4a375b5183be02ac93eb3a75c169360
  Author: Carl Ritson <carl.ritson at amd.com>
  Date:   2020-10-06 (Tue, 06 Oct 2020)

  Changed paths:
    M llvm/lib/CodeGen/VirtRegMap.cpp
    M llvm/test/CodeGen/AMDGPU/splitkit-copy-bundle.mir

  Log Message:
  -----------
  Fix reordering of instructions during VirtRegRewriter unbundling

When unbundling COPY bundles in VirtRegRewriter the start of the
bundle is not correctly referenced in the unbundling loop.

The effect of this is that unbundled instructions are sometimes
inserted out-of-order, particular in cases where multiple
reordering have been applied to avoid clobbering dependencies.
The resulting instruction sequence clobbers dependencies.

Reviewed By: foad

Differential Revision: https://reviews.llvm.org/D88821