user0/rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

move math intrinsics to their own file

Browse source
This commit is contained in:
Ralf Jung 2025-07-19 11:57:49 +02:00
parent 3430751d7e
commit 94ab2b9f15
2 changed files with 315 additions and 287 deletions
Download patch file Download diff file Expand all files Collapse all files

311
src/tools/miri/src/intrinsics/math.rs Normal file
View file

@ -0,0 +1,311 @@
use rand::Rng;
use rustc_apfloat::{self, Float, Round};
use rustc_middle::mir;
use rustc_middle::ty::{self, FloatTy};
use self::helpers::{ToHost, ToSoft};
use super::check_intrinsic_arg_count;
use crate::*;
impl<'tcx> EvalContextExt<'tcx> for crate::MiriInterpCx<'tcx> {}
pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
fn emulate_math_intrinsic(
&mut self,
intrinsic_name: &str,
_generic_args: ty::GenericArgsRef<'tcx>,
args: &[OpTy<'tcx>],
dest: &MPlaceTy<'tcx>,
) -> InterpResult<'tcx, EmulateItemResult> {
let this = self.eval_context_mut();
match intrinsic_name {
// Operations we can do with soft-floats.
"sqrtf32" => {
let [f] = check_intrinsic_arg_count(args)?;
let f = this.read_scalar(f)?.to_f32()?;
// Sqrt is specified to be fully precise.
let res = math::sqrt(f);
let res = this.adjust_nan(res, &[f]);
this.write_scalar(res, dest)?;
}
"sqrtf64" => {
let [f] = check_intrinsic_arg_count(args)?;
let f = this.read_scalar(f)?.to_f64()?;
// Sqrt is specified to be fully precise.
let res = math::sqrt(f);
let res = this.adjust_nan(res, &[f]);
this.write_scalar(res, dest)?;
}
"fmaf32" => {
let [a, b, c] = check_intrinsic_arg_count(args)?;
let a = this.read_scalar(a)?.to_f32()?;
let b = this.read_scalar(b)?.to_f32()?;
let c = this.read_scalar(c)?.to_f32()?;
let res = a.mul_add(b, c).value;
let res = this.adjust_nan(res, &[a, b, c]);
this.write_scalar(res, dest)?;
}
"fmaf64" => {
let [a, b, c] = check_intrinsic_arg_count(args)?;
let a = this.read_scalar(a)?.to_f64()?;
let b = this.read_scalar(b)?.to_f64()?;
let c = this.read_scalar(c)?.to_f64()?;
let res = a.mul_add(b, c).value;
let res = this.adjust_nan(res, &[a, b, c]);
this.write_scalar(res, dest)?;
}
"fmuladdf32" => {
let [a, b, c] = check_intrinsic_arg_count(args)?;
let a = this.read_scalar(a)?.to_f32()?;
let b = this.read_scalar(b)?.to_f32()?;
let c = this.read_scalar(c)?.to_f32()?;
let fuse: bool = this.machine.float_nondet && this.machine.rng.get_mut().random();
let res = if fuse { a.mul_add(b, c).value } else { ((a * b).value + c).value };
let res = this.adjust_nan(res, &[a, b, c]);
this.write_scalar(res, dest)?;
}
"fmuladdf64" => {
let [a, b, c] = check_intrinsic_arg_count(args)?;
let a = this.read_scalar(a)?.to_f64()?;
let b = this.read_scalar(b)?.to_f64()?;
let c = this.read_scalar(c)?.to_f64()?;
let fuse: bool = this.machine.float_nondet && this.machine.rng.get_mut().random();
let res = if fuse { a.mul_add(b, c).value } else { ((a * b).value + c).value };
let res = this.adjust_nan(res, &[a, b, c]);
this.write_scalar(res, dest)?;
}
#[rustfmt::skip]
| "fadd_fast"
| "fsub_fast"
| "fmul_fast"
| "fdiv_fast"
| "frem_fast"
=> {
let [a, b] = check_intrinsic_arg_count(args)?;
let a = this.read_immediate(a)?;
let b = this.read_immediate(b)?;
let op = match intrinsic_name {
"fadd_fast" => mir::BinOp::Add,
"fsub_fast" => mir::BinOp::Sub,
"fmul_fast" => mir::BinOp::Mul,
"fdiv_fast" => mir::BinOp::Div,
"frem_fast" => mir::BinOp::Rem,
_ => bug!(),
};
let float_finite = |x: &ImmTy<'tcx>| -> InterpResult<'tcx, bool> {
let ty::Float(fty) = x.layout.ty.kind() else {
bug!("float_finite: non-float input type {}", x.layout.ty)
};
interp_ok(match fty {
FloatTy::F16 => x.to_scalar().to_f16()?.is_finite(),
FloatTy::F32 => x.to_scalar().to_f32()?.is_finite(),
FloatTy::F64 => x.to_scalar().to_f64()?.is_finite(),
FloatTy::F128 => x.to_scalar().to_f128()?.is_finite(),
})
};
match (float_finite(&a)?, float_finite(&b)?) {
(false, false) => throw_ub_format!(
"`{intrinsic_name}` intrinsic called with non-finite value as both parameters",
),
(false, _) => throw_ub_format!(
"`{intrinsic_name}` intrinsic called with non-finite value as first parameter",
),
(_, false) => throw_ub_format!(
"`{intrinsic_name}` intrinsic called with non-finite value as second parameter",
),
_ => {}
}
let res = this.binary_op(op, &a, &b)?;
// This cannot be a NaN so we also don't have to apply any non-determinism.
// (Also, `binary_op` already called `generate_nan` if needed.)
if !float_finite(&res)? {
throw_ub_format!("`{intrinsic_name}` intrinsic produced non-finite value as result");
}
// Apply a relative error of 4ULP to simulate non-deterministic precision loss
// due to optimizations.
let res = math::apply_random_float_error_to_imm(this, res, 4)?;
this.write_immediate(*res, dest)?;
}
"float_to_int_unchecked" => {
let [val] = check_intrinsic_arg_count(args)?;
let val = this.read_immediate(val)?;
let res = this
.float_to_int_checked(&val, dest.layout, Round::TowardZero)?
.ok_or_else(|| {
err_ub_format!(
"`float_to_int_unchecked` intrinsic called on {val} which cannot be represented in target type `{:?}`",
dest.layout.ty
)
})?;
this.write_immediate(*res, dest)?;
}
// Operations that need host floats.
#[rustfmt::skip]
| "sinf32"
| "cosf32"
| "expf32"
| "exp2f32"
| "logf32"
| "log10f32"
| "log2f32"
=> {
let [f] = check_intrinsic_arg_count(args)?;
let f = this.read_scalar(f)?.to_f32()?;
let res = math::fixed_float_value(this, intrinsic_name, &[f]).unwrap_or_else(|| {
// Using host floats (but it's fine, these operations do not have
// guaranteed precision).
let host = f.to_host();
let res = match intrinsic_name {
"sinf32" => host.sin(),
"cosf32" => host.cos(),
"expf32" => host.exp(),
"exp2f32" => host.exp2(),
"logf32" => host.ln(),
"log10f32" => host.log10(),
"log2f32" => host.log2(),
_ => bug!(),
};
let res = res.to_soft();
// Apply a relative error of 4ULP to introduce some non-determinism
// simulating imprecise implementations and optimizations.
let res = math::apply_random_float_error_ulp(
this,
res,
4,
);
// Clamp the result to the guaranteed range of this function according to the C standard,
// if any.
math::clamp_float_value(intrinsic_name, res)
});
let res = this.adjust_nan(res, &[f]);
this.write_scalar(res, dest)?;
}
#[rustfmt::skip]
| "sinf64"
| "cosf64"
| "expf64"
| "exp2f64"
| "logf64"
| "log10f64"
| "log2f64"
=> {
let [f] = check_intrinsic_arg_count(args)?;
let f = this.read_scalar(f)?.to_f64()?;
let res = math::fixed_float_value(this, intrinsic_name, &[f]).unwrap_or_else(|| {
// Using host floats (but it's fine, these operations do not have
// guaranteed precision).
let host = f.to_host();
let res = match intrinsic_name {
"sinf64" => host.sin(),
"cosf64" => host.cos(),
"expf64" => host.exp(),
"exp2f64" => host.exp2(),
"logf64" => host.ln(),
"log10f64" => host.log10(),
"log2f64" => host.log2(),
_ => bug!(),
};
let res = res.to_soft();
// Apply a relative error of 4ULP to introduce some non-determinism
// simulating imprecise implementations and optimizations.
let res = math::apply_random_float_error_ulp(
this,
res,
4,
);
// Clamp the result to the guaranteed range of this function according to the C standard,
// if any.
math::clamp_float_value(intrinsic_name, res)
});
let res = this.adjust_nan(res, &[f]);
this.write_scalar(res, dest)?;
}
"powf32" => {
let [f1, f2] = check_intrinsic_arg_count(args)?;
let f1 = this.read_scalar(f1)?.to_f32()?;
let f2 = this.read_scalar(f2)?.to_f32()?;
let res =
math::fixed_float_value(this, intrinsic_name, &[f1, f2]).unwrap_or_else(|| {
// Using host floats (but it's fine, this operation does not have guaranteed precision).
let res = f1.to_host().powf(f2.to_host()).to_soft();
// Apply a relative error of 4ULP to introduce some non-determinism
// simulating imprecise implementations and optimizations.
math::apply_random_float_error_ulp(this, res, 4)
});
let res = this.adjust_nan(res, &[f1, f2]);
this.write_scalar(res, dest)?;
}
"powf64" => {
let [f1, f2] = check_intrinsic_arg_count(args)?;
let f1 = this.read_scalar(f1)?.to_f64()?;
let f2 = this.read_scalar(f2)?.to_f64()?;
let res =
math::fixed_float_value(this, intrinsic_name, &[f1, f2]).unwrap_or_else(|| {
// Using host floats (but it's fine, this operation does not have guaranteed precision).
let res = f1.to_host().powf(f2.to_host()).to_soft();
// Apply a relative error of 4ULP to introduce some non-determinism
// simulating imprecise implementations and optimizations.
math::apply_random_float_error_ulp(this, res, 4)
});
let res = this.adjust_nan(res, &[f1, f2]);
this.write_scalar(res, dest)?;
}
"powif32" => {
let [f, i] = check_intrinsic_arg_count(args)?;
let f = this.read_scalar(f)?.to_f32()?;
let i = this.read_scalar(i)?.to_i32()?;
let res = math::fixed_powi_value(this, f, i).unwrap_or_else(|| {
// Using host floats (but it's fine, this operation does not have guaranteed precision).
let res = f.to_host().powi(i).to_soft();
// Apply a relative error of 4ULP to introduce some non-determinism
// simulating imprecise implementations and optimizations.
math::apply_random_float_error_ulp(this, res, 4)
});
let res = this.adjust_nan(res, &[f]);
this.write_scalar(res, dest)?;
}
"powif64" => {
let [f, i] = check_intrinsic_arg_count(args)?;
let f = this.read_scalar(f)?.to_f64()?;
let i = this.read_scalar(i)?.to_i32()?;
let res = math::fixed_powi_value(this, f, i).unwrap_or_else(|| {
// Using host floats (but it's fine, this operation does not have guaranteed precision).
let res = f.to_host().powi(i).to_soft();
// Apply a relative error of 4ULP to introduce some non-determinism
// simulating imprecise implementations and optimizations.
math::apply_random_float_error_ulp(this, res, 4)
});
let res = this.adjust_nan(res, &[f]);
this.write_scalar(res, dest)?;
}
_ => return interp_ok(EmulateItemResult::NotSupported),
}
interp_ok(EmulateItemResult::NeedsReturn)
}
}

291
src/tools/miri/src/intrinsics/mod.rs
View file

@ -1,6 +1,7 @@
#![warn(clippy::arithmetic_side_effects)]
mod atomic;
mod math;
mod simd;
pub use self::atomic::AtomicRmwOp;
@ -8,13 +9,11 @@ pub use self::atomic::AtomicRmwOp;
#[rustfmt::skip] // prevent `use` reordering
use rand::Rng;
use rustc_abi::Size;
use rustc_apfloat::{self, Float, Round};
use rustc_middle::mir;
use rustc_middle::ty::{self, FloatTy};
use rustc_middle::{mir, ty};
use rustc_span::{Symbol, sym};
use self::atomic::EvalContextExt as _;
use self::helpers::{ToHost, ToSoft};
use self::math::EvalContextExt as _;
use self::simd::EvalContextExt as _;
use crate::*;
@ -179,288 +178,6 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
this.write_scalar(Scalar::from_bool(branch), dest)?;
}
"sqrtf32" => {
let [f] = check_intrinsic_arg_count(args)?;
let f = this.read_scalar(f)?.to_f32()?;
// Sqrt is specified to be fully precise.
let res = math::sqrt(f);
let res = this.adjust_nan(res, &[f]);
this.write_scalar(res, dest)?;
}
"sqrtf64" => {
let [f] = check_intrinsic_arg_count(args)?;
let f = this.read_scalar(f)?.to_f64()?;
// Sqrt is specified to be fully precise.
let res = math::sqrt(f);
let res = this.adjust_nan(res, &[f]);
this.write_scalar(res, dest)?;
}
#[rustfmt::skip]
| "sinf32"
| "cosf32"
| "expf32"
| "exp2f32"
| "logf32"
| "log10f32"
| "log2f32"
=> {
let [f] = check_intrinsic_arg_count(args)?;
let f = this.read_scalar(f)?.to_f32()?;
let res = math::fixed_float_value(this, intrinsic_name, &[f]).unwrap_or_else(|| {
// Using host floats (but it's fine, these operations do not have
// guaranteed precision).
let host = f.to_host();
let res = match intrinsic_name {
"sinf32" => host.sin(),
"cosf32" => host.cos(),
"expf32" => host.exp(),
"exp2f32" => host.exp2(),
"logf32" => host.ln(),
"log10f32" => host.log10(),
"log2f32" => host.log2(),
_ => bug!(),
};
let res = res.to_soft();
// Apply a relative error of 4ULP to introduce some non-determinism
// simulating imprecise implementations and optimizations.
let res = math::apply_random_float_error_ulp(
this,
res,
4,
);
// Clamp the result to the guaranteed range of this function according to the C standard,
// if any.
math::clamp_float_value(intrinsic_name, res)
});
let res = this.adjust_nan(res, &[f]);
this.write_scalar(res, dest)?;
}
#[rustfmt::skip]
| "sinf64"
| "cosf64"
| "expf64"
| "exp2f64"
| "logf64"
| "log10f64"
| "log2f64"
=> {
let [f] = check_intrinsic_arg_count(args)?;
let f = this.read_scalar(f)?.to_f64()?;
let res = math::fixed_float_value(this, intrinsic_name, &[f]).unwrap_or_else(|| {
// Using host floats (but it's fine, these operations do not have
// guaranteed precision).
let host = f.to_host();
let res = match intrinsic_name {
"sinf64" => host.sin(),
"cosf64" => host.cos(),
"expf64" => host.exp(),
"exp2f64" => host.exp2(),
"logf64" => host.ln(),
"log10f64" => host.log10(),
"log2f64" => host.log2(),
_ => bug!(),
};
let res = res.to_soft();
// Apply a relative error of 4ULP to introduce some non-determinism
// simulating imprecise implementations and optimizations.
let res = math::apply_random_float_error_ulp(
this,
res,
4,
);
// Clamp the result to the guaranteed range of this function according to the C standard,
// if any.
math::clamp_float_value(intrinsic_name, res)
});
let res = this.adjust_nan(res, &[f]);
this.write_scalar(res, dest)?;
}
"fmaf32" => {
let [a, b, c] = check_intrinsic_arg_count(args)?;
let a = this.read_scalar(a)?.to_f32()?;
let b = this.read_scalar(b)?.to_f32()?;
let c = this.read_scalar(c)?.to_f32()?;
let res = a.mul_add(b, c).value;
let res = this.adjust_nan(res, &[a, b, c]);
this.write_scalar(res, dest)?;
}
"fmaf64" => {
let [a, b, c] = check_intrinsic_arg_count(args)?;
let a = this.read_scalar(a)?.to_f64()?;
let b = this.read_scalar(b)?.to_f64()?;
let c = this.read_scalar(c)?.to_f64()?;
let res = a.mul_add(b, c).value;
let res = this.adjust_nan(res, &[a, b, c]);
this.write_scalar(res, dest)?;
}
"fmuladdf32" => {
let [a, b, c] = check_intrinsic_arg_count(args)?;
let a = this.read_scalar(a)?.to_f32()?;
let b = this.read_scalar(b)?.to_f32()?;
let c = this.read_scalar(c)?.to_f32()?;
let fuse: bool = this.machine.float_nondet && this.machine.rng.get_mut().random();
let res = if fuse { a.mul_add(b, c).value } else { ((a * b).value + c).value };
let res = this.adjust_nan(res, &[a, b, c]);
this.write_scalar(res, dest)?;
}
"fmuladdf64" => {
let [a, b, c] = check_intrinsic_arg_count(args)?;
let a = this.read_scalar(a)?.to_f64()?;
let b = this.read_scalar(b)?.to_f64()?;
let c = this.read_scalar(c)?.to_f64()?;
let fuse: bool = this.machine.float_nondet && this.machine.rng.get_mut().random();
let res = if fuse { a.mul_add(b, c).value } else { ((a * b).value + c).value };
let res = this.adjust_nan(res, &[a, b, c]);
this.write_scalar(res, dest)?;
}
"powf32" => {
let [f1, f2] = check_intrinsic_arg_count(args)?;
let f1 = this.read_scalar(f1)?.to_f32()?;
let f2 = this.read_scalar(f2)?.to_f32()?;
let res =
math::fixed_float_value(this, intrinsic_name, &[f1, f2]).unwrap_or_else(|| {
// Using host floats (but it's fine, this operation does not have guaranteed precision).
let res = f1.to_host().powf(f2.to_host()).to_soft();
// Apply a relative error of 4ULP to introduce some non-determinism
// simulating imprecise implementations and optimizations.
math::apply_random_float_error_ulp(this, res, 4)
});
let res = this.adjust_nan(res, &[f1, f2]);
this.write_scalar(res, dest)?;
}
"powf64" => {
let [f1, f2] = check_intrinsic_arg_count(args)?;
let f1 = this.read_scalar(f1)?.to_f64()?;
let f2 = this.read_scalar(f2)?.to_f64()?;
let res =
math::fixed_float_value(this, intrinsic_name, &[f1, f2]).unwrap_or_else(|| {
// Using host floats (but it's fine, this operation does not have guaranteed precision).
let res = f1.to_host().powf(f2.to_host()).to_soft();
// Apply a relative error of 4ULP to introduce some non-determinism
// simulating imprecise implementations and optimizations.
math::apply_random_float_error_ulp(this, res, 4)
});
let res = this.adjust_nan(res, &[f1, f2]);
this.write_scalar(res, dest)?;
}
"powif32" => {
let [f, i] = check_intrinsic_arg_count(args)?;
let f = this.read_scalar(f)?.to_f32()?;
let i = this.read_scalar(i)?.to_i32()?;
let res = math::fixed_powi_value(this, f, i).unwrap_or_else(|| {
// Using host floats (but it's fine, this operation does not have guaranteed precision).
let res = f.to_host().powi(i).to_soft();
// Apply a relative error of 4ULP to introduce some non-determinism
// simulating imprecise implementations and optimizations.
math::apply_random_float_error_ulp(this, res, 4)
});
let res = this.adjust_nan(res, &[f]);
this.write_scalar(res, dest)?;
}
"powif64" => {
let [f, i] = check_intrinsic_arg_count(args)?;
let f = this.read_scalar(f)?.to_f64()?;
let i = this.read_scalar(i)?.to_i32()?;
let res = math::fixed_powi_value(this, f, i).unwrap_or_else(|| {
// Using host floats (but it's fine, this operation does not have guaranteed precision).
let res = f.to_host().powi(i).to_soft();
// Apply a relative error of 4ULP to introduce some non-determinism
// simulating imprecise implementations and optimizations.
math::apply_random_float_error_ulp(this, res, 4)
});
let res = this.adjust_nan(res, &[f]);
this.write_scalar(res, dest)?;
}
#[rustfmt::skip]
| "fadd_fast"
| "fsub_fast"
| "fmul_fast"
| "fdiv_fast"
| "frem_fast"
=> {
let [a, b] = check_intrinsic_arg_count(args)?;
let a = this.read_immediate(a)?;
let b = this.read_immediate(b)?;
let op = match intrinsic_name {
"fadd_fast" => mir::BinOp::Add,
"fsub_fast" => mir::BinOp::Sub,
"fmul_fast" => mir::BinOp::Mul,
"fdiv_fast" => mir::BinOp::Div,
"frem_fast" => mir::BinOp::Rem,
_ => bug!(),
};
let float_finite = |x: &ImmTy<'tcx>| -> InterpResult<'tcx, bool> {
let ty::Float(fty) = x.layout.ty.kind() else {
bug!("float_finite: non-float input type {}", x.layout.ty)
};
interp_ok(match fty {
FloatTy::F16 => x.to_scalar().to_f16()?.is_finite(),
FloatTy::F32 => x.to_scalar().to_f32()?.is_finite(),
FloatTy::F64 => x.to_scalar().to_f64()?.is_finite(),
FloatTy::F128 => x.to_scalar().to_f128()?.is_finite(),
})
};
match (float_finite(&a)?, float_finite(&b)?) {
(false, false) => throw_ub_format!(
"`{intrinsic_name}` intrinsic called with non-finite value as both parameters",
),
(false, _) => throw_ub_format!(
"`{intrinsic_name}` intrinsic called with non-finite value as first parameter",
),
(_, false) => throw_ub_format!(
"`{intrinsic_name}` intrinsic called with non-finite value as second parameter",
),
_ => {}
}
let res = this.binary_op(op, &a, &b)?;
// This cannot be a NaN so we also don't have to apply any non-determinism.
// (Also, `binary_op` already called `generate_nan` if needed.)
if !float_finite(&res)? {
throw_ub_format!("`{intrinsic_name}` intrinsic produced non-finite value as result");
}
// Apply a relative error of 4ULP to simulate non-deterministic precision loss
// due to optimizations.
let res = math::apply_random_float_error_to_imm(this, res, 4)?;
this.write_immediate(*res, dest)?;
}
"float_to_int_unchecked" => {
let [val] = check_intrinsic_arg_count(args)?;
let val = this.read_immediate(val)?;
let res = this
.float_to_int_checked(&val, dest.layout, Round::TowardZero)?
.ok_or_else(|| {
err_ub_format!(
"`float_to_int_unchecked` intrinsic called on {val} which cannot be represented in target type `{:?}`",
dest.layout.ty
)
})?;
this.write_immediate(*res, dest)?;
}
// Other
"breakpoint" => {
let [] = check_intrinsic_arg_count(args)?;
@ -472,7 +189,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
// Make these a NOP, so we get the better Miri-native error messages.
}
_ => return interp_ok(EmulateItemResult::NotSupported),
_ => return this.emulate_math_intrinsic(intrinsic_name, generic_args, args, dest),
}
interp_ok(EmulateItemResult::NeedsReturn)