[all-commits] [llvm/llvm-project] fd9e69: [RegisterCoalescer] Avoid retrying high-cost joins...

[Jolyon via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: fd9e690cdbeb02832cc36d455bffda9e7e813785
      https://github.com/llvm/llvm-project/commit/fd9e690cdbeb02832cc36d455bffda9e7e813785
  Author: Jolyon <yangjian.c at bytedance.com>
  Date:   2026-07-21 (Tue, 21 Jul 2026)

  Changed paths:
    M llvm/lib/CodeGen/RegisterCoalescer.cpp

  Log Message:
  -----------
  [RegisterCoalescer] Avoid retrying high-cost joins for live intervals (#207976)

Recently we found a compile time problem in the case that contains much
high-cost live
interval. And normal interference failures still set `Again=true` and
can be retried
(it cost N^2 complexity). We tracks when a join failed only because of
the high-cost
guard, so that avoids putting such copies back into the retry worklist.

This reduce our huge function case from 14.6h to 12.8min in register
coalescer pass.



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