https://github.com/rust-lang/rust http://git.dreamy.place/mirrors/rust/atom?h=1.83.0 2024-10-11T21:32:56+00:00 2024-10-11T21:32:56+00:00 Jed Brown jed@jedbrown.org 2024-01-06T04:04:41+00:00 urn:sha1:0d8a978e8a55b08778ec6ee861c2c5ed6703eb6c Add intrinsics `fmuladd{f16,f32,f64,f128}`. This computes `(a * b) + c`, to be fused if the code generator determines that (i) the target instruction set has support for a fused operation, and (ii) that the fused operation is more efficient than the equivalent, separate pair of `mul` and `add` instructions. https://llvm.org/docs/LangRef.html#llvm-fmuladd-intrinsic MIRI support is included for f32 and f64. The codegen_cranelift uses the `fma` function from libc, which is a correct implementation, but without the desired performance semantic. I think this requires an update to cranelift to expose a suitable instruction in its IR. I have not tested with codegen_gcc, but it should behave the same way (using `fma` from libc). 2024-09-23T11:28:15+00:00 bjorn3 17426603+bjorn3@users.noreply.github.com 2024-09-23T11:28:15+00:00 urn:sha1:6b042f5b5d4bfe629c8440e58d4036b4dfc6ecd9 2024-09-23T11:20:46+00:00 bjorn3 17426603+bjorn3@users.noreply.github.com 2024-09-23T11:20:46+00:00 urn:sha1:b40fe1ee2826a52b2f21c31c43d06caea40885c8 2024-09-22T23:11:29+00:00 Michael Goulet michael@errs.io 2024-09-22T23:05:04+00:00 urn:sha1:c682aa162b0d41e21cc6748f4fecfe01efb69d1f 2024-09-21T00:38:11+00:00 Michael Goulet michael@errs.io 2024-09-21T00:38:11+00:00 urn:sha1:914193c8f40528fe82696e1054828de8c399882e 2024-09-14T12:43:24+00:00 Ralf Jung post@ralfj.de 2024-09-12T09:33:13+00:00 urn:sha1:60ee1b7ac6e1c18679573d4a752e6fc02790d892 2024-08-13T05:51:17+00:00 Ralf Jung post@ralfj.de 2024-08-06T10:25:37+00:00 urn:sha1:194baa820d36926cfa9128211bbd61866d49d501 2024-08-12T15:09:14+00:00 Guillaume Gomez guillaume1.gomez@gmail.com 2024-08-12T15:09:14+00:00 urn:sha1:095ca33bb6da3c1dd789eaf59461c99f4023b626 nontemporal_store: make sure that the intrinsic is truly just a hint The `!nontemporal` flag for stores in LLVM *sounds* like it is just a hint, but actually, it is not -- at least on x86, non-temporal stores need very special treatment by the programmer or else the Rust memory model breaks down. LLVM still treats these stores as-if they were normal stores for optimizations, which is [highly dubious](https://github.com/llvm/llvm-project/issues/64521). Let's avoid all that dubiousness by making our own non-temporal stores be truly just a hint, which is possible on some targets (e.g. ARM). On all other targets, non-temporal stores become regular stores. ~~Blocked on https://github.com/rust-lang/stdarch/pull/1541 propagating to the rustc repo, to make sure the `_mm_stream` intrinsics are unaffected by this change.~~ Fixes https://github.com/rust-lang/rust/issues/114582 Cc `@Amanieu` `@workingjubilee` 2024-08-09T17:18:46+00:00 bjorn3 17426603+bjorn3@users.noreply.github.com 2024-08-09T17:18:46+00:00 urn:sha1:af7ea3135deb4c2e4636d002b892c7ecf054a2e9 2024-08-05T08:57:14+00:00 Ralf Jung post@ralfj.de 2024-07-24T18:55:43+00:00 urn:sha1:28e0907111075dead53a931004b0ba6f1fe0d793