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authorSzabolcs Nagy <nsz@port70.net>2021-02-05 19:51:36 +0000
committerRich Felker <dalias@aerifal.cx>2021-02-10 14:06:50 -0500
commit964104f9f0e056cf58d9defa0b716d7756f040f6 (patch)
tree6d71a99a105627e40fd9c2a1acfa161fa9a9e39f
parentc4c38e6364323b6d83ba3428464e19987b981d7a (diff)
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math: fix expm1f overflow threshold
the threshold was wrong so expm1f overflowed to inf a bit too early
and on most targets uint32_t compare is faster than float compare so
use that.

this also fixes sinhf incorrectly returning nan for some values where
the internal expm1f overflowed.
-rw-r--r--src/math/expm1f.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/src/math/expm1f.c b/src/math/expm1f.c
index 297e0b44..09a41afe 100644
--- a/src/math/expm1f.c
+++ b/src/math/expm1f.c
@@ -16,7 +16,6 @@
 #include "libm.h"
 
 static const float
-o_threshold = 8.8721679688e+01, /* 0x42b17180 */
 ln2_hi      = 6.9313812256e-01, /* 0x3f317180 */
 ln2_lo      = 9.0580006145e-06, /* 0x3717f7d1 */
 invln2      = 1.4426950216e+00, /* 0x3fb8aa3b */
@@ -41,7 +40,7 @@ float expm1f(float x)
 			return x;
 		if (sign)
 			return -1;
-		if (x > o_threshold) {
+		if (hx > 0x42b17217) { /* x > log(FLT_MAX) */
 			x *= 0x1p127f;
 			return x;
 		}