| use rustc_apfloat::{self, Float, FloatConvert, Round}; |
| use rustc_middle::mir; |
| use rustc_middle::ty::{self, FloatTy}; |
| |
| use self::helpers::{ToHost, ToSoft}; |
| use super::check_intrinsic_arg_count; |
| use crate::*; |
| |
| fn sqrt<'tcx, F: Float + FloatConvert<F> + Into<Scalar>>( |
| this: &mut MiriInterpCx<'tcx>, |
| args: &[OpTy<'tcx>], |
| dest: &MPlaceTy<'tcx>, |
| ) -> InterpResult<'tcx> { |
| let [f] = check_intrinsic_arg_count(args)?; |
| let f = this.read_scalar(f)?; |
| let f: F = f.to_float()?; |
| // Sqrt is specified to be fully precise. |
| let res = math::sqrt(f); |
| let res = this.adjust_nan(res, &[f]); |
| this.write_scalar(res, dest) |
| } |
| |
| 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. |
| "sqrtf16" => sqrt::<rustc_apfloat::ieee::Half>(this, args, dest)?, |
| "sqrtf32" => sqrt::<rustc_apfloat::ieee::Single>(this, args, dest)?, |
| "sqrtf64" => sqrt::<rustc_apfloat::ieee::Double>(this, args, dest)?, |
| "sqrtf128" => sqrt::<rustc_apfloat::ieee::Quad>(this, args, 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) |
| } |
| } |
