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Make intrinsic fallback bodies cross-crate inlineable #121309
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Some changes occurred to MIR optimizations cc @rust-lang/wg-mir-opt |
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This change was prompted by the stage1 compiler spending 4% of its time when compiling the polymorphic-recursion MIR opt test in `unlikely`. Intrinsic fallback bodies like `unlikely` should always be inlined, it's very silly if they are not. To do this, we enable the fallback bodies to be cross-crate inlineable. Not that this matters for our workloads since the compiler never actually _uses_ the "fallback bodies", it just uses whatever was cfg(bootstrap)ped, so I've also added `#[inline]` to those.
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@bors r+ |
☀️ Test successful - checks-actions |
Finished benchmarking commit (1bb3a9f): comparison URL. Overall result: ❌✅ regressions and improvements - no action needed@rustbot label: -perf-regression Instruction countThis is a highly reliable metric that was used to determine the overall result at the top of this comment.
Max RSS (memory usage)ResultsThis is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
CyclesThis benchmark run did not return any relevant results for this metric. Binary sizeThis benchmark run did not return any relevant results for this metric. Bootstrap: 649.986s -> 649.076s (-0.14%) |
Upgrades the Rust toolchain to `nightly-2024-02-25`. The Rust compiler PRs that triggered changes in this upgrades are: * rust-lang/rust#121209 * rust-lang/rust#121309 * rust-lang/rust#120863 * rust-lang/rust#117772 * rust-lang/rust#117658 With rust-lang/rust#121309 some intrinsics became inlineable so their names became qualified. This made our `match` on the intrinsic name to fail in those cases, leaving them as unsupported constructs as in this example: ``` warning: Found the following unsupported constructs: - _RNvNtCscyGW2MM2t5j_4core10intrinsics8unlikelyCs1eohKeNmpdS_5arith (3) - caller_location (1) - foreign function (1) Verification will fail if one or more of these constructs is reachable. See https://model-checking.github.io/kani/rust-feature-support.html for more details. [...] Failed Checks: _RNvNtCscyGW2MM2t5j_4core10intrinsics8unlikelyCs1eohKeNmpdS_5arith is not currently supported by Kani. Please post your example at https://github.com/model-checking/kani/issues/new/choose File: "/home/ubuntu/.rustup/toolchains/nightly-2024-02-18-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/num/mod.rs", line 25, in core::num::<impl i8>::checked_add ``` We use `trimmed_name()` to work around this, but that may include type arguments if the intrinsic is defined on generics. So in those cases, we just take the first part of the name so we can keep the rest as before. Resolves #3044
This change was prompted by the stage1 compiler spending 4% of its time when compiling the polymorphic-recursion MIR opt test in
unlikely
.Intrinsic fallback bodies like
unlikely
should always be inlined, it's very silly if they are not. To do this, we enable the fallback bodies to be cross-crate inlineable. Not that this matters for our workloads since the compiler never actually uses the "fallback bodies", it just uses whatever was cfg(bootstrap)ped, so I've also added#[inline]
to those.See the comments for more information.
r? oli-obk