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Decrease the allowed error for cbrt

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With the correctly rounded implementation, we can reduce the ULP
requirement for `cbrt` to zero. There is still an override required for
`i586` because of the imprecise FMA.
This commit is contained in:
Trevor Gross 2025-01-25 00:31:49 +00:00
parent 2fa2b10ba4
commit 35c201c37f
1 changed files with 3 additions and 2 deletions
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5
library/compiler-builtins/libm/crates/libm-test/src/precision.rs
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@ -41,7 +41,7 @@ pub fn default_ulp(ctx: &CheckCtx) -> u32 {
| Bn::Trunc => 0,
// Operations that aren't required to be exact, but our implementations are.
Bn::Cbrt if ctx.fn_ident != Id::Cbrt => 0,
Bn::Cbrt => 0,
// Bessel functions have large inaccuracies.
Bn::J0 | Bn::J1 | Bn::Y0 | Bn::Y1 | Bn::Jn | Bn::Yn => 8_000_000,
@ -54,7 +54,6 @@ pub fn default_ulp(ctx: &CheckCtx) -> u32 {
Bn::Atan => 1,
Bn::Atan2 => 2,
Bn::Atanh => 2,
Bn::Cbrt => 1,
Bn::Cos => 1,
Bn::Cosh => 1,
Bn::Erf => 1,
@ -92,6 +91,7 @@ pub fn default_ulp(ctx: &CheckCtx) -> u32 {
}
match ctx.fn_ident {
Id::Cbrt => ulp = 2,
// FIXME(#401): musl has an incorrect result here.
Id::Fdim => ulp = 2,
Id::Sincosf => ulp = 500,
@ -119,6 +119,7 @@ pub fn default_ulp(ctx: &CheckCtx) -> u32 {
Id::Asinh => ulp = 3,
Id::Asinhf => ulp = 3,
Id::Cbrt => ulp = 1,
Id::Exp10 | Id::Exp10f => ulp = 1_000_000,
Id::Exp2 | Id::Exp2f => ulp = 10_000_000,
Id::Log1p | Id::Log1pf => ulp = 2,