6.0🍒[Observation] Optimize cancellation path to avoid excessive copies #73356
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phausler
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stephentyrone
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May 2, 2024
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Explanation: The existing code could potentially mis-optimize and create copies of the set for the cancellation tokens. This mutates it in-place to avoid those copies.
Radar: rdar://127018986
Scope: Only applies to the cancellation path inside of the Observation library
Risk: low - there are no functional changes in how the compiler is built
Testing: unit tests cover this particular case
Reviewed By: @glessard in #73288