[PATCH] D103593: [Coroutine] Sink lifetime markers after switch of suspend blocks to avoid disturbing must tail calls

[Chuanqi Xu via Phabricator via llvm-commits]

ChuanqiXu created this revision.
ChuanqiXu added reviewers: lxfind, rjmccall, junparser.
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This fixes bug 50544 <https://bugs.llvm.org/show_bug.cgi?id=50544>.

The original implementation would try to insert new lifetime markers between `coro.suspend` and the switch that uses `coro.suspends`. After lowering, it would make a pattern:

  fastcc call anything ; // should be musttail
  %0 = getelementptr ...
  lifetime.start(size, %0)
  ret void

which prevent the musttail call and it doesn't make sense actually. This patch tries to insert new lifetime markers after the switch block instead, which solves the bug and makes more sense.

Test Plan: check-all


https://reviews.llvm.org/D103593

Files:
  llvm/lib/Transforms/Coroutines/CoroFrame.cpp
  llvm/test/Transforms/Coroutines/coro-split-musttail4.ll

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