This slightly improves performance on systems with many cores and
barely affects systems with few cores.
My laptop (2 core + HT):
Before:
Benchmark 2: RUSTC=rustc /home/bjorn/Projects/cg_clif2/./dist/cargo-clif build --manifest-path /home/bjorn/Projects/cg_clif2/./download/simple-raytracer/Cargo.toml --target-dir /home/bjorn/Projects/cg_clif2/./build/simple_raytracer
Time (mean ± σ): 12.042 s ± 0.313 s [User: 29.434 s, System: 4.720 s]
Range (min … max): 11.670 s … 12.795 s 10 runs
After:
Benchmark 2: RUSTC=rustc /home/bjorn/Projects/cg_clif2/./dist/cargo-clif build --manifest-path /home/bjorn/Projects/cg_clif2/./download/simple-raytracer/Cargo.toml --target-dir /home/bjorn/Projects/cg_clif2/./build/simple_raytracer
Time (mean ± σ): 12.037 s ± 0.384 s [User: 29.960 s, System: 4.722 s]
Range (min … max): 11.673 s … 12.769 s 10 runs
Dev desktop (32 cores)
Before:
Benchmark 2: RUSTC=rustc /home/gh-bjorn3/cg_clif/./dist/cargo-clif build --manifest-path /home/gh-bjorn3/cg_clif/./download/simple-raytracer/Cargo.toml --target-dir /home/gh-bjorn3/cg_clif/./build/simple_raytracer
Time (mean ± σ): 10.425 s ± 0.104 s [User: 25.877 s, System: 5.513 s]
Range (min … max): 10.267 s … 10.640 s 10 runs
After:
Benchmark 2: RUSTC=rustc /home/gh-bjorn3/cg_clif/./dist/cargo-clif build --manifest-path /home/gh-bjorn3/cg_clif/./download/simple-raytracer/Cargo.toml --target-dir /home/gh-bjorn3/cg_clif/./build/simple_raytracer
Time (mean ± σ): 10.212 s ± 0.100 s [User: 25.918 s, System: 5.555 s]
Range (min … max): 10.079 s … 10.362 s 10 runs
This significantly improves performance. For example for the
simple-raytracer benchmark it goes from a 13% improvement over LLVM to
39% improvement over LLVM.
Sometimes it is necessary for handling vector to scalar pair transmutes,
but if the types are the same there is no need for this.
This improves runtime performance on simple-raytracer by 12%.
Use stable metric for const eval limit instead of current terminator-based logic
This patch adds a `MirPass` that inserts a new MIR instruction `ConstEvalCounter` to any loops and function calls in the CFG. This instruction is used during Const Eval to count against the `const_eval_limit`, and emit the `StepLimitReached` error, replacing the current logic which uses Terminators only.
The new method of counting loops and function calls should be more stable across compiler versions (i.e., not cause crates that compiled successfully before, to no longer compile when changes to the MIR generation/optimization are made).
Also see: #103877
Sync rustc_codegen_cranelift
For cg_clif itself there have been a couple of bug fixes since the last sync, a Cranelift update and implemented all remaining simd platform intrinsics used by `std::simd`. (`std::arch` still misses a lot though) Most of the diff is from reworking of the cg_clif build system though.
r? `@ghost`
`@rustbot` label +A-codegen +A-cranelift +T-compiler
