Loosen precision on i586 based on new tests

Author: tgross35

crates/libm-test/src/precision.rs

@@ -106,7 +106,11 @@ pub fn default_ulp(ctx: &CheckCtx) -> u32 {
         match ctx.fn_ident {
             Id::Asinh => ulp = 3,
             Id::Asinhf => ulp = 3,
+            Id::Exp10 | Id::Exp10f => ulp = 1_000_000,
+            Id::Exp2 | Id::Exp2f => ulp = 10_000_000,
+            Id::Fmaf => ulp = 1,
             Id::Log1p | Id::Log1pf => ulp = 2,
+            Id::Rint => ulp = 100_000,
             Id::Round => ulp = 1,
             Id::Tan => ulp = 2,
             _ => (),
@@ -271,15 +275,23 @@ impl MaybeOverride<(f64,)> for SpecialCase {
         }
 
         if (ctx.fn_ident == Identifier::Ceil || ctx.fn_ident == Identifier::Floor)
+            && cfg!(x86_no_sse)
             && expected.eq_repr(F::NEG_ZERO)
             && actual.eq_repr(F::ZERO)
-            && cfg!(x86_no_sse)
         {
             // FIXME: the x87 implementations do not keep the distinction between -0.0 and 0.0.
             // See https://github.com/rust-lang/libm/pull/404#issuecomment-2572399955
             return XFAIL;
         }
 
+        if (ctx.fn_ident == Identifier::Exp10 || ctx.fn_ident == Identifier::Exp2)
+            && cfg!(x86_no_sse)
+        {
+            // FIXME: i586 has very imprecise results with ULP > u32::MAX for these
+            // operations so we can't reasonably provide a limit.
+            return XFAIL;
+        }
+
         maybe_check_nan_bits(actual, expected, ctx)
     }