Add fdimf16 and fdimf128

Use the generic algorithms to provide implementations for these
routines.

library/compiler-builtins/libm/crates/libm-macros/src/shared.rs

@@ -47,7 +47,7 @@ const ALL_OPERATIONS_NESTED: &[(FloatTy, Signature, Option<Signature>, &[&str])]
         FloatTy::F16,
         Signature { args: &[Ty::F16, Ty::F16], returns: &[Ty::F16] },
         None,
-        &["copysignf16"],
+        &["copysignf16", "fdimf16"],
     ),
     (
         // `(f32, f32) -> f32`
@@ -90,7 +90,7 @@ const ALL_OPERATIONS_NESTED: &[(FloatTy, Signature, Option<Signature>, &[&str])]
         FloatTy::F128,
         Signature { args: &[Ty::F128, Ty::F128], returns: &[Ty::F128] },
         None,
-        &["copysignf128"],
+        &["copysignf128", "fdimf128"],
     ),
     (
         // `(f32, f32, f32) -> f32`