Optimize use of isnan, isinf, finite

1 files changed, 20 insertions, 0 deletions

diff --git a/sysdeps/ieee754/dbl-64/s_isinf_ns.c b/sysdeps/ieee754/dbl-64/s_isinf_ns.c
new file mode 100644
index 0000000000..065522ed80
--- /dev/null
+++ b/sysdeps/ieee754/dbl-64/s_isinf_ns.c
@@ -0,0 +1,20 @@
+/*
+ * Written by Ulrich Drepper <drepper@gmail.com>.
+ */
+
+/*
+ * __isinf_ns(x) returns != 0 if x is ±inf, else 0;
+ * no branching!
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#undef __isinf_ns
+int
+__isinf_ns (double x)
+{
+	int32_t hx,lx;
+	EXTRACT_WORDS(hx,lx,x);
+	return !(lx | ((hx & 0x7fffffff) ^ 0x7ff00000));
+}