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Allow a specific fallback function in apfloat_fallback

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`as` casts are only allowed for primitives, doing the same operations
with `rustc_apfloat` requires using functions. Add a way to specify
these separately.
This commit is contained in:
Trevor Gross 2024-05-17 22:04:49 -05:00 • committed by Trevor Gross
parent fc53fb64fc
commit a3b1dfb8d5
1 changed files with 20 additions and 6 deletions
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26
library/compiler-builtins/testcrate/src/lib.rs
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@ -276,7 +276,7 @@ macro_rules! apfloat_fallback {
// The expression to run. This expression may use `FloatTy` for its signature.
// Optionally, the final conversion back to a float can be suppressed using
// `=> no_convert` (for e.g. operations that return a bool).
$op:expr $(=> $convert:ident)?,
$op:expr $(=> $convert:ident)? $(; $apfloat_op:expr)?,
// Arguments that get passed to `$op` after converting to a float
$($arg:expr),+
$(,)?
@ -292,26 +292,40 @@ macro_rules! apfloat_fallback {
use rustc_apfloat::Float;
type FloatTy = rustc_apfloat::ieee::$apfloat_ty;
let op_res = $op( $(FloatTy::from_bits($arg.to_bits().into())),+ );
apfloat_fallback!(@convert $float_ty, op_res $(,$convert)?)
apfloat_fallback!(@inner
fty: $float_ty,
// Apply a conversion to `FloatTy` to each arg, then pass all args to `$op`
op_res: $op( $(FloatTy::from_bits($arg.to_bits().into())),+ ),
$(apfloat_op: $apfloat_op, )?
$(conv_opts: $convert,)?
args: $($arg),+
)
};
ret
}};
// Operations that do not need converting back to a float
(@convert $float_ty:ty, $val:expr, no_convert) => {
(@inner fty: $float_ty:ty, op_res: $val:expr, conv_opts: no_convert, args: $($_arg:expr),+) => {
$val
};
// Some apfloat operations return a `StatusAnd` that we need to extract the value from. This
// is the default.
(@convert $float_ty:ty, $val:expr) => {{
(@inner fty: $float_ty:ty, op_res: $val:expr, args: $($_arg:expr),+) => {{
// ignore the status, just get the value
let unwrapped = $val.value;
<$float_ty>::from_bits(FloatTy::to_bits(unwrapped).try_into().unwrap())
}};
// This is the case where we can't use the same expression for the default builtin and
// nonstandard apfloat fallbac (e.g. `as` casts in std are normal functions in apfloat, so
// two separate expressions must be specified.
(@inner
fty: $float_ty:ty, op_res: $_val:expr,
apfloat_op: $apfloat_op:expr, args: $($arg:expr),+
) => {{
$apfloat_op($($arg),+)
}};
}