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authornsz <nsz@port70.net>2012-03-20 22:49:19 +0100
committernsz <nsz@port70.net>2012-03-20 22:49:19 +0100
commit91c28f61f43ba029166772e8ac25808ea3c3dc98 (patch)
treea9993bc53514ade564171678339a14470864d8e1 /src/math/nearbyintf.c
parent8c6fc860a97f79146bf5c092d5cfb90fa6d9355a (diff)
downloadmusl-91c28f61f43ba029166772e8ac25808ea3c3dc98.tar.gz
nearbyint optimization (only clear inexact when necessary)
old code saved/restored the fenv (the new code is only as slow as that when inexact is not set before the call, but some other flag is set and the rounding is inexact, which is rare) before: bench_nearbyint_exact 5000000 N 261 ns/op bench_nearbyint_inexact_set 5000000 N 262 ns/op bench_nearbyint_inexact_unset 5000000 N 261 ns/op after: bench_nearbyint_exact 10000000 N 94.99 ns/op bench_nearbyint_inexact_set 25000000 N 65.81 ns/op bench_nearbyint_inexact_unset 10000000 N 94.97 ns/op
Diffstat (limited to 'src/math/nearbyintf.c')
-rw-r--r--src/math/nearbyintf.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/src/math/nearbyintf.c b/src/math/nearbyintf.c
index 07df8f54..39c3d73b 100644
--- a/src/math/nearbyintf.c
+++ b/src/math/nearbyintf.c
@@ -1,11 +1,17 @@
#include <fenv.h>
#include <math.h>
-float nearbyintf(float x) {
- fenv_t e;
+float nearbyintf(float x)
+{
+#ifdef FE_INEXACT
+ int e;
- fegetenv(&e);
+ e = fetestexcept(FE_INEXACT);
+#endif
x = rintf(x);
- fesetenv(&e);
+#ifdef FE_INEXACT
+ if (!e)
+ feclearexcept(FE_INEXACT);
+#endif
return x;
}