[all-commits] [llvm/llvm-project] 438a63: RegAlloc: do not consider liveins to EH-pad succes...

[Tim Northover via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 438a63e13bf89ebe21768940976a6eea6285f5ff
      https://github.com/llvm/llvm-project/commit/438a63e13bf89ebe21768940976a6eea6285f5ff
  Author: Tim Northover <t.p.northover at gmail.com>
  Date:   2021-04-29 (Thu, 29 Apr 2021)

  Changed paths:
    M llvm/lib/CodeGen/RegAllocFast.cpp
    M llvm/test/CodeGen/X86/fast-isel-cmp-branch.ll
    A llvm/test/CodeGen/X86/regalloc-tight-invoke.ll

  Log Message:
  -----------
  RegAlloc: do not consider liveins to EH-pad successors as liveout.

These registers get defined by the runtime, not the block being allocated, and
treating them as preassigned in RegAllocFast adds extra pressure, sometimes
enough to make the function unallocatable.