Sync libm with upstream FreeBSD.
Upstream SHA 78599c32efed3247d165302a1fbe8d9203e38974.
Test: treehugger
Change-Id: Ib103d211315e320df89a6f0bcb30cd8ba67dd603
diff --git a/libm/upstream-freebsd/lib/msun/ld128/s_expl.c b/libm/upstream-freebsd/lib/msun/ld128/s_expl.c
index f4c18be..5b786af 100644
--- a/libm/upstream-freebsd/lib/msun/ld128/s_expl.c
+++ b/libm/upstream-freebsd/lib/msun/ld128/s_expl.c
@@ -29,7 +29,7 @@
*/
#include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/ld128/s_expl.c 336545 2018-07-20 12:42:24Z bde $");
+__FBSDID("$FreeBSD$");
/*
* ld128 version of s_expl.c. See ../ld80/s_expl.c for most comments.
@@ -92,7 +92,10 @@
t = SUM2P(hi, lo);
/* Scale by 2**k. */
- /* XXX sparc64 multiplication is so slow that scalbnl() is faster. */
+ /*
+ * XXX sparc64 multiplication was so slow that scalbnl() is faster,
+ * but performance on aarch64 and riscv hasn't yet been quantified.
+ */
if (k >= LDBL_MIN_EXP) {
if (k == LDBL_MAX_EXP)
RETURNI(t * 2 * 0x1p16383L);