Inline cfg(bootstrap) version of debug_assertions intrinsic
#121112
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This speeds up the stage1 build of the library by about 10s on my computer.
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Ah, in bootstrap, not the version used later. Yup, makes sense to me. @bors r+ |
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☔ The latest upstream changes (presumably #120500) made this pull request unmergeable. Please resolve the merge conflicts. |
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I think have a nicer and more effective solution to fix the rustc perf impact. |
Noratrieb
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…aethlin Always inline check in `assert_unsafe_precondition` with cfg(debug_assertions) The current complexities in `assert_unsafe_precondition` are delicately balancing several concerns, among them compile times for the cases where there are no debug assertions. This comes at a large runtime cost when the assertions are enabled, making the debug assertion compiler a lot slower, which is very annoying. To avoid this, we always inline the check when building with debug assertions. Numbers (compiling stage1 library after touching core): - master: 80s - just adding `#[inline(always)]` to the `cfg(bootstrap)` `debug_assertions` (equivalent to a bootstrap bump (uhh, i just realized that i was on a slightly outdated master so this bump might have happened already), (rust-lang#121112)): 67s - this: 54s So this seems like a good solution. I think we can still get the same run-time perf improvements for other users too by massaging this code further (see my other PR about adding `#[rustc_no_mir_inline]` rust-lang#121114) but this is a simpler step that solves the imminent problem of "holy shit my rustc is sooo slow". Funny consequence: This now means compiling the standard library with dbeug assertions makes it faster (than without, when using debug assertions downstream)! r? `@saethlin` (or anyone else if someone wants to review this) fixes rust-lang#121110, supposedly
Noratrieb
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Feb 20, 2024
…aethlin Always inline check in `assert_unsafe_precondition` with cfg(debug_assertions) The current complexities in `assert_unsafe_precondition` are delicately balancing several concerns, among them compile times for the cases where there are no debug assertions. This comes at a large runtime cost when the assertions are enabled, making the debug assertion compiler a lot slower, which is very annoying. To avoid this, we always inline the check when building with debug assertions. Numbers (compiling stage1 library after touching core): - master: 80s - just adding `#[inline(always)]` to the `cfg(bootstrap)` `debug_assertions` (equivalent to a bootstrap bump (uhh, i just realized that i was on a slightly outdated master so this bump might have happened already), (rust-lang#121112)): 67s - this: 54s So this seems like a good solution. I think we can still get the same run-time perf improvements for other users too by massaging this code further (see my other PR about adding `#[rustc_no_mir_inline]` rust-lang#121114) but this is a simpler step that solves the imminent problem of "holy shit my rustc is sooo slow". Funny consequence: This now means compiling the standard library with dbeug assertions makes it faster (than without, when using debug assertions downstream)! r? ``@saethlin`` (or anyone else if someone wants to review this) fixes rust-lang#121110, supposedly
Noratrieb
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Feb 20, 2024
…aethlin Always inline check in `assert_unsafe_precondition` with cfg(debug_assertions) The current complexities in `assert_unsafe_precondition` are delicately balancing several concerns, among them compile times for the cases where there are no debug assertions. This comes at a large runtime cost when the assertions are enabled, making the debug assertion compiler a lot slower, which is very annoying. To avoid this, we always inline the check when building with debug assertions. Numbers (compiling stage1 library after touching core): - master: 80s - just adding `#[inline(always)]` to the `cfg(bootstrap)` `debug_assertions` (equivalent to a bootstrap bump (uhh, i just realized that i was on a slightly outdated master so this bump might have happened already), (rust-lang#121112)): 67s - this: 54s So this seems like a good solution. I think we can still get the same run-time perf improvements for other users too by massaging this code further (see my other PR about adding `#[rustc_no_mir_inline]` rust-lang#121114) but this is a simpler step that solves the imminent problem of "holy shit my rustc is sooo slow". Funny consequence: This now means compiling the standard library with dbeug assertions makes it faster (than without, when using debug assertions downstream)! r? ```@saethlin``` (or anyone else if someone wants to review this) fixes rust-lang#121110, supposedly
rust-timer
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Feb 20, 2024
Rollup merge of rust-lang#121196 - Nilstrieb:the-clever-solution, r=saethlin Always inline check in `assert_unsafe_precondition` with cfg(debug_assertions) The current complexities in `assert_unsafe_precondition` are delicately balancing several concerns, among them compile times for the cases where there are no debug assertions. This comes at a large runtime cost when the assertions are enabled, making the debug assertion compiler a lot slower, which is very annoying. To avoid this, we always inline the check when building with debug assertions. Numbers (compiling stage1 library after touching core): - master: 80s - just adding `#[inline(always)]` to the `cfg(bootstrap)` `debug_assertions` (equivalent to a bootstrap bump (uhh, i just realized that i was on a slightly outdated master so this bump might have happened already), (rust-lang#121112)): 67s - this: 54s So this seems like a good solution. I think we can still get the same run-time perf improvements for other users too by massaging this code further (see my other PR about adding `#[rustc_no_mir_inline]` rust-lang#121114) but this is a simpler step that solves the imminent problem of "holy shit my rustc is sooo slow". Funny consequence: This now means compiling the standard library with dbeug assertions makes it faster (than without, when using debug assertions downstream)! r? ```@saethlin``` (or anyone else if someone wants to review this) fixes rust-lang#121110, supposedly
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This speeds up the stage1 build of the library by about 10s on my computer.
helps with #121110