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//! Various number casting functions
use crate::prelude::*;
pub(crate) fn clif_intcast(
fx: &mut FunctionCx<'_, '_, '_>,
val: Value,
to: Type,
signed: bool,
) -> Value {
let from = fx.bcx.func.dfg.value_type(val);
match (from, to) {
// equal
(_, _) if from == to => val,
// extend
(_, _) if to.wider_or_equal(from) => {
if signed {
fx.bcx.ins().sextend(to, val)
} else {
fx.bcx.ins().uextend(to, val)
}
}
// reduce
(_, _) => fx.bcx.ins().ireduce(to, val),
}
}
pub(crate) fn clif_int_or_float_cast(
fx: &mut FunctionCx<'_, '_, '_>,
from: Value,
from_signed: bool,
to_ty: Type,
to_signed: bool,
) -> Value {
let from_ty = fx.bcx.func.dfg.value_type(from);
if from_ty.is_int() && to_ty.is_int() {
// int-like -> int-like
clif_intcast(
fx,
from,
to_ty,
// This is correct as either from_signed == to_signed (=> this is trivially correct)
// Or from_clif_ty == to_clif_ty, which means this is a no-op.
from_signed,
)
} else if from_ty.is_int() && to_ty.is_float() {
if from_ty == types::I128 {
// _______ss__f_
// __float tisf: i128 -> f32
// __float tidf: i128 -> f64
// __floatuntisf: u128 -> f32
// __floatuntidf: u128 -> f64
let name = format!(
"__float{sign}ti{flt}f",
sign = if from_signed { "" } else { "un" },
flt = match to_ty {
types::F32 => "s",
types::F64 => "d",
_ => unreachable!("{:?}", to_ty),
},
);
let from_rust_ty = if from_signed { fx.tcx.types.i128 } else { fx.tcx.types.u128 };
let to_rust_ty = match to_ty {
types::F32 => fx.tcx.types.f32,
types::F64 => fx.tcx.types.f64,
_ => unreachable!(),
};
return fx
.easy_call(&name, &[CValue::by_val(from, fx.layout_of(from_rust_ty))], to_rust_ty)
.load_scalar(fx);
}
// int-like -> float
if from_signed {
fx.bcx.ins().fcvt_from_sint(to_ty, from)
} else {
fx.bcx.ins().fcvt_from_uint(to_ty, from)
}
} else if from_ty.is_float() && to_ty.is_int() {
let val = if to_ty == types::I128 {
// _____sssf___
// __fix sfti: f32 -> i128
// __fix dfti: f64 -> i128
// __fixunssfti: f32 -> u128
// __fixunsdfti: f64 -> u128
let name = format!(
"__fix{sign}{flt}fti",
sign = if to_signed { "" } else { "uns" },
flt = match from_ty {
types::F32 => "s",
types::F64 => "d",
_ => unreachable!("{:?}", to_ty),
},
);
let from_rust_ty = match from_ty {
types::F32 => fx.tcx.types.f32,
types::F64 => fx.tcx.types.f64,
_ => unreachable!(),
};
let to_rust_ty = if to_signed { fx.tcx.types.i128 } else { fx.tcx.types.u128 };
fx.easy_call(&name, &[CValue::by_val(from, fx.layout_of(from_rust_ty))], to_rust_ty)
.load_scalar(fx)
} else if to_ty == types::I8 || to_ty == types::I16 {
// FIXME implement fcvt_to_*int_sat.i8/i16
let val = if to_signed {
fx.bcx.ins().fcvt_to_sint_sat(types::I32, from)
} else {
fx.bcx.ins().fcvt_to_uint_sat(types::I32, from)
};
let (min, max) = match (to_ty, to_signed) {
(types::I8, false) => (0, i64::from(u8::MAX)),
(types::I16, false) => (0, i64::from(u16::MAX)),
(types::I8, true) => (i64::from(i8::MIN), i64::from(i8::MAX)),
(types::I16, true) => (i64::from(i16::MIN), i64::from(i16::MAX)),
_ => unreachable!(),
};
let min_val = fx.bcx.ins().iconst(types::I32, min);
let max_val = fx.bcx.ins().iconst(types::I32, max);
let val = if to_signed {
let has_underflow = fx.bcx.ins().icmp_imm(IntCC::SignedLessThan, val, min);
let has_overflow = fx.bcx.ins().icmp_imm(IntCC::SignedGreaterThan, val, max);
let bottom_capped = fx.bcx.ins().select(has_underflow, min_val, val);
fx.bcx.ins().select(has_overflow, max_val, bottom_capped)
} else {
let has_overflow = fx.bcx.ins().icmp_imm(IntCC::UnsignedGreaterThan, val, max);
fx.bcx.ins().select(has_overflow, max_val, val)
};
fx.bcx.ins().ireduce(to_ty, val)
} else if to_signed {
fx.bcx.ins().fcvt_to_sint_sat(to_ty, from)
} else {
fx.bcx.ins().fcvt_to_uint_sat(to_ty, from)
};
if let Some(false) = fx.tcx.sess.opts.unstable_opts.saturating_float_casts {
return val;
}
let is_not_nan = fx.bcx.ins().fcmp(FloatCC::Equal, from, from);
let zero = fx.bcx.ins().iconst(to_ty, 0);
fx.bcx.ins().select(is_not_nan, val, zero)
} else if from_ty.is_float() && to_ty.is_float() {
// float -> float
match (from_ty, to_ty) {
(types::F32, types::F64) => fx.bcx.ins().fpromote(types::F64, from),
(types::F64, types::F32) => fx.bcx.ins().fdemote(types::F32, from),
_ => from,
}
} else {
unreachable!("cast value from {:?} to {:?}", from_ty, to_ty);
}
}
|
