Commit Graph

15 Commits

Author SHA1 Message Date
Joseph Myers
bfff8b1bec Update copyright dates with scripts/update-copyrights. 2017-01-01 00:14:16 +00:00
Joseph Myers
cb864fe0ec Do not call __nan in scalb functions.
When libm functions return a NaN: if it is for NaN input, it should be
computed from that input (e.g. adding it to itself), so that payloads
are propagated and signaling NaNs quieted, while if it is for non-NaN
input, it should be produced by a computation such as
(x - x) / (x - x), which raises "invalid" at the same time as
producing an appropriate NaN, so avoiding any need for a call to
feraiseexcept.

Various libm functions, however, call __nan ("") (or __nanf or __nanl)
to determine the NaN to return, together with using feraiseexcept
(FE_INVALID) to raise the exception.  sysdeps/generic/math_private.h
has an optimization for those functions with constant "" argument so
this doesn't actually involve a call to the __nan function, but it is
still not the preferred approach for producing NaNs.  (The optimized
code also always uses the NAN macro, i.e. produces a default NaN for
float converted to whatever the target type is, and on some
architectures that may not be the same as the preferred default NaN
for double or long double.)

This patch fixes the scalb functions to use the conventional method of
generating NaNs and raising "invalid" with an appropriate
computation.  (Most instances of this issue are in the complex
functions, where it can more readily be fixed once they have been made
type-generic and so only a third as many places need fixing.  Some of
the complex functions use __nan ("") + __nan (""), where the addition
serves no purpose whatsoever.)

Tested for x86_64 and x86.

	* math/e_scalb.c: Do not include <fenv.h>.
	(invalid_fn): Do calculation resulting in NaN instead of raising
	FE_INVALID and returning a NaN explicitly.
	* math/e_scalbf.c: Do not include <fenv.h>.
	(invalid_fn): Do calculation resulting in NaN instead of raising
	FE_INVALID and returning a NaN explicitly.
	* math/e_scalbl.c: Do not include <fenv.h>.
	(invalid_fn): Do calculation resulting in NaN instead of raising
	FE_INVALID and returning a NaN explicitly.
2016-08-04 20:50:31 +00:00
Joseph Myers
f7a9f785e5 Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
Wilco Dijkstra
d81f90ccd0 This patch renames all uses of __isinf*, __isnan*, __finite* and __signbit* to use standard C99 macros. This has no effect on generated code. 2015-06-03 15:41:36 +01:00
Joseph Myers
b168057aaa Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
Joseph Myers
ea6029b19c Fix scalb spurious "invalid" exceptions (bug 16770).
This patch fixes bug 16770, spurious "invalid" exceptions from scalb
when testing whether the second argument is an integer, by inserting
appropriate range checks to determine whether a cast to int is safe.
(Note that invalid_fn is a function that handles both nonintegers and
large integers, distinguishing them reliably using functions such as
__rint; note also that there are no issues with scalb needing to avoid
spurious "inexact" exceptions - it's an old-POSIX XSI function, not a
standard C function bound to an IEEE 754 operation - although the
return value is still fully determined.)

Tested x86_64 and x86.

	[BZ #16770]
	* math/e_scalb.c (__ieee754_scalb): Check second argument is not
	too large before casting to int.
	* math/e_scalbf.c (__ieee754_scalbf): Likewise.
	* math/e_scalbl.c (__ieee754_scalbl): Likewise.
	* math/libm-test.inc (scalb_test_data): Add more tests.
2014-03-29 17:22:14 +00:00
Ondřej Bílka
a1ffb40e32 Use glibc_likely instead __builtin_expect. 2014-02-10 15:07:12 +01:00
Allan McRae
d4697bc93d Update copyright notices with scripts/update-copyrights 2014-01-01 22:00:23 +10:00
Joseph Myers
568035b787 Update copyright notices with scripts/update-copyrights. 2013-01-02 19:05:09 +00:00
Paul Eggert
59ba27a63a Replace FSF snail mail address with URLs. 2012-02-09 23:18:22 +00:00
Ulrich Drepper
0ac5ae2335 Optimize libm
libm is now somewhat integrated with gcc's -ffinite-math-only option
and lots of the wrapper functions have been optimized.
2011-10-12 11:27:51 -04:00
Ulrich Drepper
9277c06437 Use private math_private.h in files in math/ 2011-10-08 05:16:04 -04:00
Ulrich Drepper
9d13fb2413 Moved to csu/errno-loc.c. 2005-12-14 15:06:39 +00:00
Ulrich Drepper
a334319f65 (CFLAGS-tst-align.c): Add -mpreferred-stack-boundary=4. 2004-12-22 20:10:10 +00:00
Jakub Jelinek
0ecb606cb6 2.5-18.1 2007-07-12 18:26:36 +00:00