| author |  kj4tmp <kj4tmp@gmail.com> 2026-01-28 22:42:45-08:00 |
| committer |  Andrew Kelley <andrew@ziglang.org> 2026-02-13 11:30:19-08:00 |
| log | 004872baec3fc71236ee6503a6e0885a4bae7dd0 |
| tree | aae7c591afd02265e8d23443089a0992f4fd311c |
| parent | 3dc2a1f9ac572e1205cc2202e12f4d948ca67fd5 |
zig libc: acosf: fix fp exceptions
some fp exceptions are prohibited by zig test-libc (libc-test).
Promoting to f64 prevents vectorization of some floating point
divisions. The vectorization has unused lanes which contain zero. On
division the lanes containing zero are divided and trigger the INVALID
fp flags.1 files changed, 7 insertions(+), 3 deletions(-)
lib- std
- math
lib/std/math/acos.zig+7-3
| ... | ... | @@ -81,9 +81,13 @@ fn rationalApproxBinary32(z: f32) f32 { |
| 81 | 81 | const pS2: f32 = -8.6563630030e-03; |
| 82 | 82 | const qS1: f32 = -7.0662963390e-01; |
| 83 | 83 | |
| 84 | const p = z * (pS0 + z * (pS1 + z * pS2)); | |
| 85 | const q = 1.0 + z * qS1; | |
| 86 | return p / q; | |
| 84 | // f64 is used instead of f32 to avoid | |
| 85 | // a vectorization on x86_64. The vectorization | |
| 86 | // causes extra floating point execeptions | |
| 87 | // that are prohibited by libc-test. | |
| 88 | const p: f64 = @as(f64, @floatCast(z)) * (pS0 + z * (pS1 + z * pS2)); | |
| 89 | const q: f64 = 1.0 + z * qS1; | |
| 90 | return @floatCast(p / q); | |
| 87 | 91 | } |
| 88 | 92 | |
| 89 | 93 | fn acosBinary32(x: f32) f32 { |