glibc/sysdeps
Joseph Myers 58307649fb Fix hypot sNaN handling (bug 20940).
TS 18661-1 generally defines libm functions taking sNaN arguments to
return qNaN and raise "invalid", even for the cases where a
corresponding qNaN argument would not result in a qNaN return.  This
includes hypot with one argument being an infinity and the other being
an sNaN.  This patch duly fixes hypot implementatations in glibc
(generic and powerpc) to ensure qNaN, computed by arithmetic on the
arguments, is returned in that case.

Various implementations do their checks for infinities and NaNs inline
by manipulating the representations of the arguments.  For simplicity,
this patch just uses issignaling to check for sNaN arguments.  This
could be inlined like the existing code (with due care about reversed
quiet NaN conventions, for implementations where that is relevant),
but given that all these checks are in cases where it's already known
at least one argument is not finite, which should be the uncommon
case, that doesn't seem worthwhile unless performance issues are
observed in practice.

Tested for x86_64, x86, mips64 and powerpc.

	[BZ #20940]
	* sysdeps/ieee754/dbl-64/e_hypot.c (__ieee754_hypot): Do not
	return Inf for arguments Inf and sNaN.
	* sysdeps/ieee754/flt-32/e_hypotf.c (__ieee754_hypotf): Likewise.
	* sysdeps/ieee754/ldbl-128/e_hypotl.c (__ieee754_hypotl):
	Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_hypotl.c (__ieee754_hypotl):
	Likewise.
	* sysdeps/ieee754/ldbl-96/e_hypotl.c (__ieee754_hypotl): Likewise.
	* sysdeps/powerpc/fpu/e_hypot.c (TEST_INF_NAN): Do not return Inf
	for arguments Inf and sNaN.  When returning a NaN, compute it by
	arithmetic on the arguments.
	* sysdeps/powerpc/fpu/e_hypotf.c (TEST_INF_NAN): Likewise.
	* math/libm-test.inc (pow_test_data): Add tests of sNaN arguments.
2016-12-07 01:16:36 +00:00
..
aarch64 aarch64: Use explicit offsets in _dl_tlsdesc_dynamic 2016-12-02 16:52:57 +01:00
alpha Add missing hidden_def (__sigsetjmp). 2016-12-01 20:49:25 +00:00
arm Refactor FP_FAST_* into bits/fp-fast.h. 2016-11-29 01:45:00 +00:00
generic ld.so: Remove __libc_memalign 2016-11-30 16:23:58 +01:00
gnu
hppa Add missing hidden_def (__sigsetjmp). 2016-12-01 20:49:25 +00:00
i386 Fix x86_64/x86 powl handling of sNaN arguments (bug 20916). 2016-12-06 00:33:19 +00:00
ia64 Refactor FP_ILOGB* out of bits/mathdef.h. 2016-12-01 02:56:55 +00:00
ieee754 Fix hypot sNaN handling (bug 20940). 2016-12-07 01:16:36 +00:00
init_array
m68k Refactor FP_ILOGB* out of bits/mathdef.h. 2016-12-01 02:56:55 +00:00
mach Fix hurd __access_noerrno implementation. 2016-11-18 16:49:08 -02:00
microblaze Remove cached PID/TID in clone 2016-11-24 19:38:51 -02:00
mips Add missing hidden_def (__sigsetjmp). 2016-12-01 20:49:25 +00:00
nacl Add llogb, llogbf, llogbl. 2016-12-02 01:42:49 +00:00
nios2 Remove cached PID/TID in clone 2016-11-24 19:38:51 -02:00
nptl Remove cached PID/TID in clone 2016-11-24 19:38:51 -02:00
posix
powerpc Fix hypot sNaN handling (bug 20940). 2016-12-07 01:16:36 +00:00
pthread
s390 S390: Regenerate ULPs. 2016-12-02 12:52:36 +01:00
sh Add missing hidden_def (__sigsetjmp). 2016-12-01 20:49:25 +00:00
sparc Add missing hidden_def (__sigsetjmp). 2016-12-01 20:49:25 +00:00
tile Add missing hidden_def (__sigsetjmp). 2016-12-01 20:49:25 +00:00
unix Use C11-like atomics instead of plain memory accesses in x86 lock elision. 2016-12-05 16:19:43 +01:00
wordsize-32
wordsize-64
x86 Use C11-like atomics instead of plain memory accesses in x86 lock elision. 2016-12-05 16:19:43 +01:00
x86_64 Fix x86_64/x86 powl handling of sNaN arguments (bug 20916). 2016-12-06 00:33:19 +00:00