[all-commits] [llvm/llvm-project] 156092: [RegisterCoalescer] Extend a subrange if needed wh...

[Krzysztof Parzyszek via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 156092bbcc0782b049da3e346cad59b92438ce72
      https://github.com/llvm/llvm-project/commit/156092bbcc0782b049da3e346cad59b92438ce72
  Author: Krzysztof Parzyszek <kparzysz at quicinc.com>
  Date:   2020-05-04 (Mon, 04 May 2020)

  Changed paths:
    M llvm/lib/CodeGen/RegisterCoalescer.cpp
    A llvm/test/CodeGen/Hexagon/regalloc-coal-extend-short-subrange.mir

  Log Message:
  -----------
  [RegisterCoalescer] Extend a subrange if needed when filling range gap

Register live ranges may have had gaps that after coalescing should be
removed. This is done by adding a new segment to the range, and merging
it with neighboring segments. When doing so, do not assume that each
subrange of the register ended at the same index. If a subrange ended
earlier, adding this segment could make the live range invalid.
Instead, if the subrange is not live at the start of the segment,
extend it first.