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Add f16 inline ASM support for RISC-V #126530

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merged 1 commit into from
Jun 22, 2024

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This PR adds f16 inline ASM support for RISC-V. A FIXME is left for f128 support as LLVM does not support the required Q (Quad-Precision Floating-Point) extension yet.

Relevant issue: #125398
Tracking issue: #116909

@rustbot label +F-f16_and_f128

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rustbot commented Jun 15, 2024

r? @cjgillot

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@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. F-f16_and_f128 `#![feature(f16)]`, `#![feature(f128)]` labels Jun 15, 2024
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r? compiler

@rustbot rustbot assigned lcnr and unassigned cjgillot Jun 17, 2024
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lcnr commented Jun 17, 2024

r? compiler

@rustbot rustbot assigned nnethercote and unassigned lcnr Jun 17, 2024
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Looks ok to me, though I don't know anything about RISC-V. @tgross35, does it look ok to you?

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tgross35 commented Jun 17, 2024

I also don't know RISC-V :) (@MabezDev and @jessebraham might, based on the embedded wg teams).

It looks consistent with #126417 so I think it is probably fine. Amanieu did the review on that one if you prefer to pass it off.

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Ok, let's do r? @Amanieu

@rustbot rustbot assigned Amanieu and unassigned nnethercote Jun 17, 2024
let value = bx.bitcast(value, bx.type_i16());
let value = bx.zext(value, bx.type_i32());
let value = bx.or(value, bx.const_u32(0xFFFF_0000));
bx.bitcast(value, bx.type_f32())
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Does LLVM not support using f16 directly here? I expect this would result in much better codegen.

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@beetrees beetrees Jun 18, 2024

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Unfortunately not. Regardless, LLVM's codegen isn't very good around when NaN-boxing needs to occur at the moment anyway; for example, an identity function will needlessly re-NaN-box an argument that is already guaranteed to be NaN-boxed.

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My reading of the LLVM code is that it will accept f16 directly if the zfhmin feature is enabled for the current function. Can you use f16 directly in this case and only do the manual conversion to/from f32 if zfhmin is not available?

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Done

{
let value = bx.bitcast(value, bx.type_i32());
let value = bx.trunc(value, bx.type_i16());
bx.bitcast(value, bx.type_f16())
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Same here.

compiler/rustc_target/src/asm/riscv.rs Show resolved Hide resolved
@@ -913,6 +915,46 @@ fn llvm_asm_scalar_type<'ll>(cx: &CodegenCx<'ll, '_>, scalar: Scalar) -> &'ll Ty
}
}

fn function_target_features<'ll>(builder: &Builder<'_, 'll, '_>) -> impl Iterator<Item = &'ll str> {
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You can use self.tcx.asm_target_features(instance.def_id()).contains(&feature) instead and avoid all this logic. It's used earlier in this file to convert unsupported registers to clobbers.

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Done

@@ -1029,6 +1037,16 @@ fn llvm_fixup_input<'ll, 'tcx>(
_ => value,
}
}
(InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::freg), Abi::Scalar(s))
if s.primitive() == Primitive::Float(Float::F16)
&& !bx.tcx.asm_target_features(instance.def_id()).contains(&sym::zfhmin) =>
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This needs to check for zfh as well. We currently won't automatically enable zfhmin if you only enable zfh for a function with #[target_feature] because rustc isn't aware of feature dependencies.

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Added. I've also improved the test to check that manual NaN-boxing is being avoided when zfhmin is enabled.

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Amanieu commented Jun 21, 2024

@bors r+

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bors commented Jun 21, 2024

📌 Commit 771e44e has been approved by Amanieu

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 21, 2024
bors added a commit to rust-lang-ci/rust that referenced this pull request Jun 22, 2024
…kingjubilee

Rollup of 7 pull requests

Successful merges:

 - rust-lang#126530 (Add `f16` inline ASM support for RISC-V)
 - rust-lang#126712 (Migrate `relocation-model`, `error-writing-dependencies` and `crate-name-priority` `run-make` tests to rmake)
 - rust-lang#126722 (Add method to get `FnAbi` of function pointer)
 - rust-lang#126787 (Add direct accessors for memory addresses in `Machine` (for Miri))
 - rust-lang#126798 ([fuchsia-test-runner] Remove usage of kw_only)
 - rust-lang#126809 (Remove stray `.` from error message)
 - rust-lang#126811 (Add a tidy rule to check that fluent messages and attrs don't end in `.`)

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit e7956cd into rust-lang:master Jun 22, 2024
6 checks passed
@rustbot rustbot added this to the 1.81.0 milestone Jun 22, 2024
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request Jun 22, 2024
Rollup merge of rust-lang#126530 - beetrees:f16-inline-asm-riscv, r=Amanieu

Add `f16` inline ASM support for RISC-V

This PR adds `f16` inline ASM support for RISC-V. A `FIXME` is left for `f128` support as LLVM does not support the required `Q` (Quad-Precision Floating-Point) extension yet.

Relevant issue: rust-lang#125398
Tracking issue: rust-lang#116909

`@rustbot` label +F-f16_and_f128
@beetrees beetrees deleted the f16-inline-asm-riscv branch June 22, 2024 20:46
jaisnan pushed a commit to jaisnan/rust-dev that referenced this pull request Jul 29, 2024
Update Rust toolchain from nightly-2024-06-22 to nightly-2024-06-23
without any other source changes.
This is an automatically generated pull request. If any of the CI checks
fail, manual intervention is required. In such a case, review the
changes at https://github.com/rust-lang/rust from
rust-lang@c1b336c
up to
rust-lang@3cb521a.
The log for this commit range is:
rust-lang@3cb521a434 Auto merge of
rust-lang#126761 - GuillaumeGomez:unsafe_extern_blocks, r=spastorino
rust-lang@a0f01c3c10 Auto merge of
rust-lang#126838 - matthiaskrgr:rollup-qkop22o, r=matthiaskrgr
rust-lang@dc9a08f535 Rollup merge of
rust-lang#126552 - fee1-dead-contrib:rmfx, r=compiler-errors
rust-lang@162120b4fa Rollup merge of
rust-lang#126318 - Kobzol:bootstrap-perf, r=onur-ozkan
rust-lang@f3ced9d540 Rollup merge of
rust-lang#126140 - eduardosm:stabilize-fs_try_exists, r=Amanieu
rust-lang@f944afe380 Auto merge of
rust-lang#116113 - kpreid:arcmut, r=dtolnay
rust-lang@88c3db57e4 Generalize
`{Rc,Arc}::make_mut()` to unsized types.
rust-lang@a9a4830d25 Replace
`WriteCloneIntoRaw` with `CloneToUninit`.
rust-lang@ec201b8650 Add
`core::clone::CloneToUninit`.
rust-lang@81da6a6d40 Make `effects` an
incomplete feature
rust-lang@ac47dbad50 Auto merge of
rust-lang#126824 - GuillaumeGomez:rollup-sybv8o7, r=GuillaumeGomez
rust-lang@d265538016 Rollup merge of
rust-lang#126823 - GuillaumeGomez:migrate-run-make-inline-always-many-cgu,
r=Kobzol
rust-lang@25bcc7d130 Rollup merge of
rust-lang#126731 - Kobzol:bootstrap-cmd-refactor, r=onur-ozkan
rust-lang@399c5cabdd Rollup merge of
rust-lang#126723 - estebank:dot-dot-dot, r=Nadrieril
rust-lang@3ed2cd74b5 Rollup merge of
rust-lang#126686 - fmease:dump-preds-n-item-bounds, r=compiler-errors
rust-lang@07e8b3ac01 Rollup merge of
rust-lang#126555 - beetrees:f16-inline-asm-arm, r=Amanieu
rust-lang@d03d6c0fea Auto merge of
rust-lang#126750 - scottmcm:less-unlikely, r=jhpratt
rust-lang@e7dfd4a913 Migrate
`run-make/inline-always-many-cgu` to `rmake.rs`
rust-lang@d9962bb4d8 Make `read_dir`
method take a mutable callback
rust-lang@f1b0d54ca9 Auto merge of
rust-lang#126816 - weihanglo:update-cargo, r=weihanglo
rust-lang@0bd58d8122 Apply review
comments.
rust-lang@250586cb2e Wrap std `Output` in
`CommandOutput`
rust-lang@f0aceed540 Auto merge of
rust-lang#126817 - workingjubilee:rollup-0rg0k55, r=workingjubilee
rust-lang@38bd7a0fcb Add
`#[rustc_dump_{predicates,item_bounds}]`
rust-lang@1916b3d57f Rollup merge of
rust-lang#126811 - compiler-errors:tidy-ftl, r=estebank
rust-lang@539090e5cd Rollup merge of
rust-lang#126809 - estebank:wording-tweak, r=oli-obk
rust-lang@b9ab6c3501 Rollup merge of
rust-lang#126798 - miguelfrde:master, r=tmandry
rust-lang@9498d5cf2f Rollup merge of
rust-lang#126787 - Strophox:get-bytes, r=RalfJung
rust-lang@1f9793f1aa Rollup merge of
rust-lang#126722 - adwinwhite:ptr_fn_abi, r=celinval
rust-lang@84b0922565 Rollup merge of
rust-lang#126712 - Oneirical:bootest-constestllation, r=jieyouxu
rust-lang@e7956cd994 Rollup merge of
rust-lang#126530 - beetrees:f16-inline-asm-riscv, r=Amanieu
rust-lang@10e1f5d212 Auto merge of
rust-lang#124101 - the8472:pidfd-methods, r=cuviper
rust-lang@2c65a24b8c Update cargo
rust-lang@fcae62649e Auto merge of
rust-lang#126758 - spastorino:avoid-safe-outside-unsafe-blocks, r=compiler-errors
rust-lang@ffd72b1700 Fix remaining cases
rust-lang@ea681ef281 Add a tidy rule to
make sure that diagnostics don't end in periods
rust-lang@8abf149bde to extract a pidfd
we must consume the child
rust-lang@0787c7308c Add PidFd::{kill,
wait, try_wait}
rust-lang@5d5892e966 Remove stray `.`
from error message
rust-lang@d94a40516e
[fuchsia-test-runner] Remove usage of kw_only
rust-lang@771e44ebd3 Add `f16` inline ASM
support for RISC-V
rust-lang@753fb070bb Add `f16` inline ASM
support for 32-bit ARM
rust-lang@22831ed117 Do not allow safe
usafe on static and fn items
rust-lang@a6a83d3d4e bless tests
rust-lang@b512bf6f77 add as_ptr to trait
AllocBytes, fix 2 impls; add pub fn get_bytes_unchecked_raw in
allocation.rs; add pub fn get_alloc_bytes_unchecked_raw[_mut] in
memory.rs
rust-lang@02aaea1803 update intrinsic
const param counting
rust-lang@3b14b756d8 Remove
`feature(effects)` from the standard library
rust-lang@a314f7363a Stop using
`unlikely` in `strict_*` methods
rust-lang@225796a2df Add method to get
`FnAbi` of function pointer
rust-lang@630c3adb14 Add regression test
for `unsafe_extern_blocks`
rust-lang@bb9a3ef90c Implement
`unsafe_extern_blocks` feature in rustdoc
rust-lang@3c0a4bc915 rewrite
crate-name-priority to rmake
rust-lang@bc12972bcd Slightly refactor
the dumping of HIR analysis data
rust-lang@3fe4d134dd Appease `clippy`
rust-lang@c15293407f Remove unused import
rust-lang@5c4318d02c Implement `run_cmd`
in terms of `run_tracked`
rust-lang@0de7b92cc6 Remove
`run_delaying_failure`
rust-lang@e933cfb13c Remove
`run_quiet_delaying_failure`
rust-lang@949e667d3f Remove `run_quiet`
rust-lang@a12f541a18 Implement new
command execution logic
rust-lang@9fd7784b97 Fix `...` in
multline code-skips in suggestions
rust-lang@f22b5afa6a rewrite
error-writing-dependencies to rmake
rust-lang@75ee1d74a9 rewrite
relocation-model to rmake
rust-lang@87d2e61428 Add `x perf` command
for profiling the compiler using `rustc-perf`
rust-lang@fd44aca2aa Copy `rustc-fake`
binary when building the `rustc-perf` tool
rust-lang@9e0b76201b Add `RustcPerf`
bootstrap tool
rust-lang@9ec178df0b Add `cargo_args` to
`ToolBuild`
rust-lang@6a04dfe78c Rename
`std::fs::try_exists` to `std::fs::exists` and stabilize fs_try_exists

Co-authored-by: celinval <35149715+celinval@users.noreply.github.com>
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F-f16_and_f128 `#![feature(f16)]`, `#![feature(f128)]` S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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