Add compiler support for parsing f16 and f128

Author: tgross35

compiler/rustc_ast/src/util/literal.rs

@@ -276,8 +276,10 @@ fn filtered_float_lit(
         Some(suffix) => LitKind::Float(
             symbol,
             ast::LitFloatType::Suffixed(match suffix {
+                sym::f16 => ast::FloatTy::F16,
                 sym::f32 => ast::FloatTy::F32,
                 sym::f64 => ast::FloatTy::F64,
+                sym::f128 => ast::FloatTy::F128,
                 _ => return Err(LitError::InvalidFloatSuffix(suffix)),
             }),
         ),

compiler/rustc_middle/src/mir/interpret/value.rs

@@ -3,7 +3,7 @@ use std::fmt;
 use either::{Either, Left, Right};
 
 use rustc_apfloat::{
-    ieee::{Double, Single},
+    ieee::{Double, Half, Quad, Single},
     Float,
 };
 use rustc_macros::HashStable;
@@ -201,6 +201,11 @@ impl<Prov> Scalar<Prov> {
         Self::from_int(i, cx.data_layout().pointer_size)
     }
 
+    #[inline]
+    pub fn from_f16(f: Half) -> Self {
+        Scalar::Int(f.into())
+    }
+
     #[inline]
     pub fn from_f32(f: Single) -> Self {
         Scalar::Int(f.into())
@@ -211,6 +216,11 @@ impl<Prov> Scalar<Prov> {
         Scalar::Int(f.into())
     }
 
+    #[inline]
+    pub fn from_f128(f: Quad) -> Self {
+        Scalar::Int(f.into())
+    }
+
     /// This is almost certainly not the method you want!  You should dispatch on the type
     /// and use `to_{u8,u16,...}`/`scalar_to_ptr` to perform ptr-to-int / int-to-ptr casts as needed.
     ///

compiler/rustc_middle/src/ty/consts/int.rs

@@ -1,4 +1,4 @@
-use rustc_apfloat::ieee::{Double, Single};
+use rustc_apfloat::ieee::{Double, Half, Quad, Single};
 use rustc_apfloat::Float;
 use rustc_errors::{DiagArgValue, IntoDiagnosticArg};
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
@@ -450,6 +450,22 @@ impl TryFrom<ScalarInt> for char {
     }
 }
 
+impl From<Half> for ScalarInt {
+    #[inline]
+    fn from(f: Half) -> Self {
+        // We trust apfloat to give us properly truncated data.
+        Self { data: f.to_bits(), size: NonZero::new((Half::BITS / 8) as u8).unwrap() }
+    }
+}
+
+impl TryFrom<ScalarInt> for Half {
+    type Error = Size;
+    #[inline]
+    fn try_from(int: ScalarInt) -> Result<Self, Size> {
+        int.to_bits(Size::from_bytes(4)).map(Self::from_bits)
+    }
+}
+
 impl From<Single> for ScalarInt {
     #[inline]
     fn from(f: Single) -> Self {
@@ -482,6 +498,22 @@ impl TryFrom<ScalarInt> for Double {
     }
 }
 
+impl From<Quad> for ScalarInt {
+    #[inline]
+    fn from(f: Quad) -> Self {
+        // We trust apfloat to give us properly truncated data.
+        Self { data: f.to_bits(), size: NonZero::new((Quad::BITS / 8) as u8).unwrap() }
+    }
+}
+
+impl TryFrom<ScalarInt> for Quad {
+    type Error = Size;
+    #[inline]
+    fn try_from(int: ScalarInt) -> Result<Self, Size> {
+        int.to_bits(Size::from_bytes(8)).map(Self::from_bits)
+    }
+}
+
 impl fmt::Debug for ScalarInt {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // Dispatch to LowerHex below.

compiler/rustc_mir_build/src/build/mod.rs

@@ -1,7 +1,7 @@
 use crate::build::expr::as_place::PlaceBuilder;
 use crate::build::scope::DropKind;
 use itertools::Itertools;
-use rustc_apfloat::ieee::{Double, Single};
+use rustc_apfloat::ieee::{Double, Half, Quad, Single};
 use rustc_apfloat::Float;
 use rustc_ast::attr;
 use rustc_data_structures::fx::FxHashMap;
@@ -1053,7 +1053,8 @@ pub(crate) fn parse_float_into_scalar(
 ) -> Option<Scalar> {
     let num = num.as_str();
     match float_ty {
-        ty::FloatTy::F16 => unimplemented!("f16_f128"),
+        // FIXME(f16_f128): When available, compare to the library parser as with `f32` and `f64`
+        ty::FloatTy::F16 => num.parse::<Half>().ok().map(Scalar::from_f16),
         ty::FloatTy::F32 => {
             let Ok(rust_f) = num.parse::<f32>() else { return None };
             let mut f = num
@@ -1100,7 +1101,8 @@ pub(crate) fn parse_float_into_scalar(
 
             Some(Scalar::from_f64(f))
         }
-        ty::FloatTy::F128 => unimplemented!("f16_f128"),
+        // FIXME(f16_f128): When available, compare to the library parser as with `f32` and `f64`
+        ty::FloatTy::F128 => num.parse::<Quad>().ok().map(Scalar::from_f128),
     }
 }