Skip to content

intrinsics: unify rint, roundeven, nearbyint in a single round_ties_even intrinsic #136543

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Feb 24, 2025
Merged

intrinsics: unify rint, roundeven, nearbyint in a single round_ties_even intrinsic #136543

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
04e7a10
intrinsics: unify rint, roundeven, nearbyint in a single round_ties_e…
RalfJung Feb 4, 2025
d1b34ac
make the new intrinsics safe
RalfJung Feb 22, 2025
b9d0555
add stdarch compatibility hack
RalfJung Feb 23, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 7 additions & 9 deletions compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -340,14 +340,10 @@ fn codegen_float_intrinsic_call<'tcx>(
sym::ceilf64 => ("ceil", 1, fx.tcx.types.f64, types::F64),
sym::truncf32 => ("truncf", 1, fx.tcx.types.f32, types::F32),
sym::truncf64 => ("trunc", 1, fx.tcx.types.f64, types::F64),
sym::rintf32 => ("rintf", 1, fx.tcx.types.f32, types::F32),
sym::rintf64 => ("rint", 1, fx.tcx.types.f64, types::F64),
sym::round_ties_even_f32 => ("rintf", 1, fx.tcx.types.f32, types::F32),
sym::round_ties_even_f64 => ("rint", 1, fx.tcx.types.f64, types::F64),
sym::roundf32 => ("roundf", 1, fx.tcx.types.f32, types::F32),
sym::roundf64 => ("round", 1, fx.tcx.types.f64, types::F64),
sym::roundevenf32 => ("roundevenf", 1, fx.tcx.types.f32, types::F32),
sym::roundevenf64 => ("roundeven", 1, fx.tcx.types.f64, types::F64),
sym::nearbyintf32 => ("nearbyintf", 1, fx.tcx.types.f32, types::F32),
sym::nearbyintf64 => ("nearbyint", 1, fx.tcx.types.f64, types::F64),
sym::sinf32 => ("sinf", 1, fx.tcx.types.f32, types::F32),
sym::sinf64 => ("sin", 1, fx.tcx.types.f64, types::F64),
sym::cosf32 => ("cosf", 1, fx.tcx.types.f32, types::F32),
Expand Down Expand Up @@ -399,16 +395,18 @@ fn codegen_float_intrinsic_call<'tcx>(
| sym::ceilf64
| sym::truncf32
| sym::truncf64
| sym::nearbyintf32
| sym::nearbyintf64
| sym::round_ties_even_f32
| sym::round_ties_even_f64
| sym::sqrtf32
| sym::sqrtf64 => {
let val = match intrinsic {
sym::fabsf32 | sym::fabsf64 => fx.bcx.ins().fabs(args[0]),
sym::floorf32 | sym::floorf64 => fx.bcx.ins().floor(args[0]),
sym::ceilf32 | sym::ceilf64 => fx.bcx.ins().ceil(args[0]),
sym::truncf32 | sym::truncf64 => fx.bcx.ins().trunc(args[0]),
sym::nearbyintf32 | sym::nearbyintf64 => fx.bcx.ins().nearest(args[0]),
sym::round_ties_even_f32 | sym::round_ties_even_f64 => {
fx.bcx.ins().nearest(args[0])
}
Copy link
Member Author

@RalfJung RalfJung Feb 4, 2025 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This means the cranelift backend will actually change behavior with this PR -- the round_ties_even functions will lower to the "nearest" instruction rather than to rint libcalls. @bjorn3 is that okay?

I am also surprised to not see a case for round here (rounding half-way cases away from zero); is that the one rounding mode cranelit does not support natively?

Copy link
Contributor

@tgross35 tgross35 Feb 5, 2025 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

If this ever lowers to nearbyint then we do not currently provide that in libm so there may be linking problems on targets without a system libm. I don't expect this to be a problem for cranelift though.

sym::sqrtf32 | sym::sqrtf64 => fx.bcx.ins().sqrt(args[0]),
_ => unreachable!(),
};
Expand Down
9 changes: 3 additions & 6 deletions compiler/rustc_codegen_gcc/src/intrinsic/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -84,14 +84,11 @@ fn get_simple_intrinsic<'gcc, 'tcx>(
sym::ceilf64 => "ceil",
sym::truncf32 => "truncf",
sym::truncf64 => "trunc",
sym::rintf32 => "rintf",
sym::rintf64 => "rint",
sym::nearbyintf32 => "nearbyintf",
sym::nearbyintf64 => "nearbyint",
// We match the LLVM backend and lower this to `rint`.
sym::round_ties_even_f32 => "rintf",
sym::round_ties_even_f64 => "rint",
sym::roundf32 => "roundf",
sym::roundf64 => "round",
sym::roundevenf32 => "roundevenf",
sym::roundevenf64 => "roundeven",
sym::abort => "abort",
_ => return None,
};
Expand Down
22 changes: 8 additions & 14 deletions compiler/rustc_codegen_llvm/src/intrinsic.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -126,15 +126,14 @@ fn get_simple_intrinsic<'ll>(
sym::truncf64 => "llvm.trunc.f64",
sym::truncf128 => "llvm.trunc.f128",

sym::rintf16 => "llvm.rint.f16",
sym::rintf32 => "llvm.rint.f32",
sym::rintf64 => "llvm.rint.f64",
sym::rintf128 => "llvm.rint.f128",

sym::nearbyintf16 => "llvm.nearbyint.f16",
sym::nearbyintf32 => "llvm.nearbyint.f32",
sym::nearbyintf64 => "llvm.nearbyint.f64",
sym::nearbyintf128 => "llvm.nearbyint.f128",
// We could use any of `rint`, `nearbyint`, or `roundeven`
// for this -- they are all identical in semantics when
// assuming the default FP environment.
// `rint` is what we used for $forever.
sym::round_ties_even_f16 => "llvm.rint.f16",
sym::round_ties_even_f32 => "llvm.rint.f32",
sym::round_ties_even_f64 => "llvm.rint.f64",
sym::round_ties_even_f128 => "llvm.rint.f128",

sym::roundf16 => "llvm.round.f16",
sym::roundf32 => "llvm.round.f32",
Expand All @@ -143,11 +142,6 @@ fn get_simple_intrinsic<'ll>(

sym::ptr_mask => "llvm.ptrmask",

sym::roundevenf16 => "llvm.roundeven.f16",
sym::roundevenf32 => "llvm.roundeven.f32",
sym::roundevenf64 => "llvm.roundeven.f64",
sym::roundevenf128 => "llvm.roundeven.f128",

_ => return None,
};
Some(cx.get_intrinsic(llvm_name))
Expand Down
22 changes: 8 additions & 14 deletions compiler/rustc_hir_analysis/src/check/intrinsic.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -137,6 +137,10 @@ pub fn intrinsic_operation_unsafety(tcx: TyCtxt<'_>, intrinsic_id: LocalDefId) -
| sym::fmul_algebraic
| sym::fdiv_algebraic
| sym::frem_algebraic
| sym::round_ties_even_f16
| sym::round_ties_even_f32
| sym::round_ties_even_f64
| sym::round_ties_even_f128
| sym::const_eval_select => hir::Safety::Safe,
_ => hir::Safety::Unsafe,
};
Expand Down Expand Up @@ -398,26 +402,16 @@ pub fn check_intrinsic_type(
sym::truncf64 => (0, 0, vec![tcx.types.f64], tcx.types.f64),
sym::truncf128 => (0, 0, vec![tcx.types.f128], tcx.types.f128),

sym::rintf16 => (0, 0, vec![tcx.types.f16], tcx.types.f16),
sym::rintf32 => (0, 0, vec![tcx.types.f32], tcx.types.f32),
sym::rintf64 => (0, 0, vec![tcx.types.f64], tcx.types.f64),
sym::rintf128 => (0, 0, vec![tcx.types.f128], tcx.types.f128),

sym::nearbyintf16 => (0, 0, vec![tcx.types.f16], tcx.types.f16),
sym::nearbyintf32 => (0, 0, vec![tcx.types.f32], tcx.types.f32),
sym::nearbyintf64 => (0, 0, vec![tcx.types.f64], tcx.types.f64),
sym::nearbyintf128 => (0, 0, vec![tcx.types.f128], tcx.types.f128),
sym::round_ties_even_f16 => (0, 0, vec![tcx.types.f16], tcx.types.f16),
sym::round_ties_even_f32 => (0, 0, vec![tcx.types.f32], tcx.types.f32),
sym::round_ties_even_f64 => (0, 0, vec![tcx.types.f64], tcx.types.f64),
sym::round_ties_even_f128 => (0, 0, vec![tcx.types.f128], tcx.types.f128),

sym::roundf16 => (0, 0, vec![tcx.types.f16], tcx.types.f16),
sym::roundf32 => (0, 0, vec![tcx.types.f32], tcx.types.f32),
sym::roundf64 => (0, 0, vec![tcx.types.f64], tcx.types.f64),
sym::roundf128 => (0, 0, vec![tcx.types.f128], tcx.types.f128),

sym::roundevenf16 => (0, 0, vec![tcx.types.f16], tcx.types.f16),
sym::roundevenf32 => (0, 0, vec![tcx.types.f32], tcx.types.f32),
sym::roundevenf64 => (0, 0, vec![tcx.types.f64], tcx.types.f64),
sym::roundevenf128 => (0, 0, vec![tcx.types.f128], tcx.types.f128),

sym::volatile_load | sym::unaligned_volatile_load => {
(1, 0, vec![Ty::new_imm_ptr(tcx, param(0))], param(0))
}
Expand Down
16 changes: 4 additions & 12 deletions compiler/rustc_span/src/symbol.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1337,10 +1337,6 @@ symbols! {
native_link_modifiers_whole_archive,
natvis_file,
ne,
nearbyintf128,
nearbyintf16,
nearbyintf32,
nearbyintf64,
needs_allocator,
needs_drop,
needs_panic_runtime,
Expand Down Expand Up @@ -1655,20 +1651,16 @@ symbols! {
return_position_impl_trait_in_trait,
return_type_notation,
rhs,
rintf128,
rintf16,
rintf32,
rintf64,
riscv_target_feature,
rlib,
ropi,
ropi_rwpi: "ropi-rwpi",
rotate_left,
rotate_right,
roundevenf128,
roundevenf16,
roundevenf32,
roundevenf64,
round_ties_even_f128,
round_ties_even_f16,
round_ties_even_f32,
round_ties_even_f64,
roundf128,
roundf16,
roundf32,
Expand Down
Loading
Loading