encode region::Scope using fewer bytes #44809
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This wraps unsizing coercions within an additional level of `commit_if_ok`, which rolls back type variables if the unsizing coercion fails. This prevents a large amount of type-variables from accumulating while type-checking a large function, e.g. shaving 2GB off one of the 4GB peaks in rust-lang#36799.
this should produce more error stability
Now that region::Scope is no longer interned, its size is more important. This PR encodes region::Scope in 8 bytes instead of 12, which should speed up region inference somewhat (perf testing needed) and should improve the margins on rust-lang#36799 by 64MB (that's not a lot, I did this PR mostly to speed up region inference).
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Nice trick! @bors r+ |
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📌 Commit c10b23e has been approved by |
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@bors p=1 (perf) |
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⌛ Testing commit c10b23e with merge 93d48986d0b8c12cd2f29431485fee2ebccd0fca... |
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💔 Test failed - status-travis |
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@bors r=eddyb |
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📌 Commit 7bb0923 has been approved by |
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encode region::Scope using fewer bytes Now that region::Scope is no longer interned, its size is more important. This PR encodes region::Scope in 8 bytes instead of 12, which should speed up region inference somewhat (perf testing needed) and should improve the margins on #36799 by 64MB (that's not a lot, I did this PR mostly to speed up region inference). This is a perf-sensitive PR. Please don't roll me up. r? @eddyb This is based on #44743 so I could get more accurate measurements on #36799.
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☀️ Test successful - status-appveyor, status-travis |
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Now that region::Scope is no longer interned, its size is more important. This PR encodes region::Scope in 8 bytes instead of 12, which should speed up region inference somewhat (perf testing needed) and should improve the margins on #36799 by 64MB (that's not a lot, I did this PR mostly to speed up region inference).
This is a perf-sensitive PR. Please don't roll me up.
r? @eddyb
This is based on #44743 so I could get more accurate measurements on #36799.