[LICM/Exclusivity] Hoist (some) conflicting begin_accesses out of loops #19023
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Consider the attached test cases: We have a begin_access [dynamic] to a global inside of a loop There’s a nested conflict on said access due to an apply() instruction between the begin and end accesses. LICM is currently very conservative: If there are any function calls inside of the loop that conflict with begin and end access, we do not hoist out of the loop. However, if all conflicting applies are “sandwiched” between the begin and end access. So there’s no reason we can’t hoist out of the loop. See radar rdar://problem/43660965 - this improves some internal benchmarks by over 3X
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@atrick can you please review? |
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@swift-ci Please test |
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Build failed |
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@swift-ci Please clean test Linux |
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Build failed |
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Linux test failure is unrelated - debug info problem on the bots: |
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@swift-ci Please smoke test Linux |
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Consider the attached test cases:
We have a begin_access [dynamic] to a global inside of a loop
There’s a nested conflict on said access due to an apply() instruction between the begin and end accesses.
LICM is currently very conservative: If there are any function calls inside of the loop that conflict with begin and end access, we do not hoist out of the loop.
However, if all conflicting applies are “sandwiched” between the begin and end access. So there’s no reason we can’t hoist out of the loop.
See radar rdar://problem/43660965 - this improves some internal benchmarks by over 3X