22
rustc_codegen_gcc: Progress Report #25
(blog.antoyo.xyz)
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 01 Sep 2023
22 points (100.0% liked)
Rust
5744 readers
78 users here now
Welcome to the Rust community! This is a place to discuss about the Rust programming language.
Wormhole
Credits
- The icon is a modified version of the official rust logo (changing the colors to a gradient and black background)
founded 1 year ago
MODERATORS
That's very impressive for gcc. IIRC adding restrict to LLVM triiggered major bugs and miscompilations at least for the first two attempts. As they said they need to do a crater run to be sure, but even passing the initial smoke test is an achievement for gcc.
However, I'm surprised the code is “only” 3% faster using restric annotation. IIRC the speed-ups were about 5% for LLVM so maybe there is still some performance to gain on the gcc side?
To be fair, I heard that some bugs for
restrictfixed in LLVM were also fixed in GCC as a result of finding them using the LLVM codegen of rustc.For the 3%, this is in only one particular benchmark. Since I was curious, I compiled my test program with the LLVM codegen and disabled
noalias: there's also a 3% performance improvement.