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authorJoseph Myers <joseph@codesourcery.com>2014-03-31 14:57:53 +0000
committerJoseph Myers <joseph@codesourcery.com>2014-03-31 14:57:53 +0000
commit8795b4a443a8f19d279e0c1bc99b73d1f5aec166 (patch)
tree8459e5f7ad0c37157c894a314664d296ab4d0555 /math/w_scalbl.c
parent54fa2475d37b9c7afd903eb970362e50ec76f01e (diff)
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Set errno for scalb errors (bug 6803, bug 6804).
This patch fixes the default mode of scalb to set errno (bugs 6803 and 6804). Previously, the _LIB_VERSION == _SVID_ mode would set errno but only in some relevant cases, and with various peculiarities (such as errno setting when an exact infinity or zero result arises with an argument to scalb being an infinity). This patch leaves this mode bug-compatible, while making the default mode set errno in accordance with normal practice (so an exact infinity from an infinite argument is not an error, and nor is an exact zero result). gen-libm-test.pl is taught new notation such as ERRNO_PLUS_OFLOW to facilitate writing the tests of errno setting for underflow / overflow in libm-test.inc. Note that bug 6803 also covers scalbn and scalbln, but this patch only addresses the scalb parts of that bug (along with the whole of bug 6804). Tested x86_64 and x86. [BZ #6803] [BZ #6804] * math/w_scalb.c (__scalb): For non-SVID mode, check result and set errno as appropriate. * math/w_scalbf.c (__scalbf): Likewise. * math/w_scalbl.c (__scalbl): Likewise. * math/gen-libm-test.pl (parse_args): Handle ERRNO_PLUS_OFLOW, ERRNO_MINUS_OFLOW, ERRNO_PLUS_UFLOW and ERRNO_MINUS_UFLOW. * math/libm-test.inc (scalb_test_data): Add errno expectations. Add more NaN tests.
Diffstat (limited to 'math/w_scalbl.c')
-rw-r--r--math/w_scalbl.c30
1 files changed, 27 insertions, 3 deletions
diff --git a/math/w_scalbl.c b/math/w_scalbl.c
index cffaa67..40cc68e 100644
--- a/math/w_scalbl.c
+++ b/math/w_scalbl.c
@@ -45,8 +45,32 @@ sysv_scalbl (long double x, long double fn)
long double
__scalbl (long double x, long double fn)
{
- return (__builtin_expect (_LIB_VERSION == _SVID_, 0)
- ? sysv_scalbl (x, fn)
- : __ieee754_scalbl (x, fn));
+ if (__glibc_unlikely (_LIB_VERSION == _SVID_))
+ return sysv_scalbl (x, fn);
+ else
+ {
+ long double z = __ieee754_scalbl (x, fn);
+
+ if (__glibc_unlikely (!__finitel (z) || z == 0.0L))
+ {
+ if (__isnanl (z))
+ {
+ if (!__isnanl (x) && !__isnanl (fn))
+ __set_errno (EDOM);
+ }
+ else if (__isinf_nsl (z))
+ {
+ if (!__isinf_nsl (x) && !__isinf_nsl (fn))
+ __set_errno (ERANGE);
+ }
+ else
+ {
+ /* z == 0. */
+ if (x != 0.0L && !__isinf_nsl (fn))
+ __set_errno (ERANGE);
+ }
+ }
+ return z;
+ }
}
weak_alias (__scalbl, scalbl)