Avoid quadratic growth of functions due to cleanups #31390
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Awesome stuff @dotdash! 🌴 |
| exit_label.branch(bcx_out, prev_llbb); | ||
| prev_llbb = bcx_in.llbb; | ||
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| scope.add_cached_early_exit(exit_label, prev_llbb); | ||
| let len = scope.cleanups.len(); |
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Nit: move this a little bit up and reuse len inside take(scope.cleanups.len() - skip).
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Overall LGTM. |
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Nits addressed. |
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No test? |
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Test added. |
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@bors r+ |
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📌 Commit 8923122 has been approved by |
| // CHECK: call{{.*}}SomeUniqueName{{.*}}drop | ||
| // CHECK: call{{.*}}SomeUniqueName{{.*}}drop | ||
| // CHECK-NOT: call{{.*}}SomeUniqueName{{.*}}drop | ||
| // The next line checks for the 0 that ends the function definition |
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The 0 is a typo'd }, right?
If a new cleanup is added to a cleanup scope, the cached exits for that scope are cleared, so all previous cleanups have to be translated again. In the worst case this means that we get N distinct landing pads where the last one has N cleanups, then N-1 and so on. As new cleanups are to be executed before older ones, we can instead cache the number of already translated cleanups in addition to the block that contains them, and then only translate new ones, if any and then jump to the cached ones, getting away with linear growth instead. For the crate in rust-lang#31381 this reduces the compile time for an optimized build from >20 minutes (I cancelled the build at that point) to about 11 seconds. Testing a few crates that come with rustc show compile time improvements somewhere between 1 and 8%. The "big" winner being rustc_platform_intrinsics which features code similar to that in rust-lang#31381. Fixes rust-lang#31381
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@bors r=nagisa Typo fixed. |
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📌 Commit 8c0f4f5 has been approved by |
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If a new cleanup is added to a cleanup scope, the cached exits for that scope are cleared, so all previous cleanups have to be translated again. In the worst case this means that we get N distinct landing pads where the last one has N cleanups, then N-1 and so on. As new cleanups are to be executed before older ones, we can instead cache the number of already translated cleanups in addition to the block that contains them, and then only translate new ones, if any and then jump to the cached ones, getting away with linear growth instead. For the crate in rust-lang#31381 this reduces the compile time for an optimized build from >20 minutes (I cancelled the build at that point) to about 11 seconds. Testing a few crates that come with rustc show compile time improvements somewhere between 1 and 8%. The "big" winner being rustc_platform_intrinsics which features code similar to that in rust-lang#31381. Fixes rust-lang#31381
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If a new cleanup is added to a cleanup scope, the cached exits for that scope are cleared, so all previous cleanups have to be translated again. In the worst case this means that we get N distinct landing pads where the last one has N cleanups, then N-1 and so on. As new cleanups are to be executed before older ones, we can instead cache the number of already translated cleanups in addition to the block that contains them, and then only translate new ones, if any and then jump to the cached ones, getting away with linear growth instead. For the crate in #31381 this reduces the compile time for an optimized build from >20 minutes (I cancelled the build at that point) to about 11 seconds. Testing a few crates that come with rustc show compile time improvements somewhere between 1 and 8%. The "big" winner being rustc_platform_intrinsics which features code similar to that in #31381. Fixes #31381
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If a new cleanup is added to a cleanup scope, the cached exits for that
scope are cleared, so all previous cleanups have to be translated
again. In the worst case this means that we get N distinct landing pads
where the last one has N cleanups, then N-1 and so on.
As new cleanups are to be executed before older ones, we can instead
cache the number of already translated cleanups in addition to the
block that contains them, and then only translate new ones, if any and
then jump to the cached ones, getting away with linear growth instead.
For the crate in #31381 this reduces the compile time for an optimized
build from >20 minutes (I cancelled the build at that point) to about 11
seconds. Testing a few crates that come with rustc show compile time
improvements somewhere between 1 and 8%. The "big" winner being
rustc_platform_intrinsics which features code similar to that in #31381.
Fixes #31381