[PATCH] D88821: Fix reordering of instructions during VirtRegRewriter unbundling

[Carl Ritson via Phabricator via llvm-commits]

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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.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D88821

Files:
  llvm/lib/CodeGen/VirtRegMap.cpp
  llvm/test/CodeGen/AMDGPU/splitkit-copy-bundle.mir

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