Fix removal of trivial exception-handling blocks from spawned tasks #273
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…s and their spawned tasks.
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This PR fixes the removal of trivial exception-handling blocks from spawned tasks.
Previously, SimplifyCFG would remove these blocks incrementally, mainly using standard logic for serial code. But as of commit 333cdd4 in llvm/llvm-project, this process ends up transforming
invokes in spawned tasks tocalls marked with the does-not-throw attribute. That attribute prevents subsequent Tapir lowering from reintroducing landingpads for those calls, specifically to cleanup parallel-runtime data structures.To resolve this issue, this PR revises the logic to remove trivial exception-handling blocks in tasks as a unit. This change allows these blocks to be removed without any associated
invokebeing marked does-not-throw. Most existing regression tests for the removal of exception-handling blocks from tasks are therefore still correct.This PR should resolve the runtime crash mentioned in issue #266.