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glibc/sysdeps/i386
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Joseph Myers 30dcf959d2 Avoid "inexact" exceptions in i386/x86_64 trunc functions (bug 15479). 
As discussed in
<https://sourceware.org/ml/libc-alpha/2016-05/msg00577.html>, TS
18661-1 disallows ceil, floor, round and trunc functions from raising
the "inexact" exception, in accordance with general IEEE 754 semantics
for when that exception is raised.  Fixing this for x87 floating point
is more complicated than for the other versions of these functions,
because they use the frndint instruction that raises "inexact" and
this can only be avoided by saving and restoring the whole
floating-point environment.

As I noted in
<https://sourceware.org/ml/libc-alpha/2016-06/msg00128.html>, I have
now implemented a GCC option -fno-fp-int-builtin-inexact for GCC 7,
such that GCC will inline these functions on x86, without caring about
"inexact", when the default -ffp-int-builtin-inexact is in effect.
This allows users to get optimized code depending on the options they
pass to the compiler, while making the out-of-line functions follow TS
18661-1 semantics and avoid "inexact".

This patch duly fixes the out-of-line trunc function implementations
to avoid "inexact", in the same way as the nearbyint implementations.

I do not know how the performance of implementations such as these
based on saving the environment and changing the rounding mode
temporarily compares to that of the C versions or SSE 4.1 versions (of
course, for 32-bit x86 SSE implementations still need to get the
return value in an x87 register); it's entirely possible other
implementations could be faster in some cases.

Tested for x86_64 and x86.

	[BZ #15479]
	* sysdeps/i386/fpu/s_trunc.S (__trunc): Save and restore
	floating-point environment rather than just control word.
	* sysdeps/i386/fpu/s_truncf.S (__truncf): Likewise.
	* sysdeps/i386/fpu/s_truncl.S (__truncl): Save and restore
	floating-point environment, with "invalid" exceptions merged in,
	rather than just control word.
	* sysdeps/x86_64/fpu/s_truncl.S (__truncl): Likewise.
	* math/libm-test.inc (trunc_test_data): Do not allow spurious
	"inexact" exceptions.
2016-06-27 17:26:52 +00:00
..
fpu Avoid "inexact" exceptions in i386/x86_64 trunc functions (bug 15479). 2016-06-27 17:26:52 +00:00
i586 Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
i686 Use generic fdim on more architectures (bug 6796, bug 20255, bug 20256). 2016-06-14 16:04:19 +00:00
i786
nptl elf: Consolidate machine-agnostic DTV definitions in <dl-dtv.h> 2016-06-20 14:31:40 +02:00
sys Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
____longjmp_chk.S
__longjmp.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
abort-instr.h
add_n.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
addmul_1.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
asm-syntax.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
atomic-machine.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
backtrace.c Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
bcopy.S Add i386 memset and memcpy assembly functions 2015-08-27 09:04:54 -07:00
bsd-_setjmp.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
bsd-setjmp.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
bzero.S Add i386 memset and memcpy assembly functions 2015-08-27 09:04:54 -07:00
cacheinfo.c Move sysdeps/x86_64/cacheinfo.c to sysdeps/x86 2016-05-08 08:49:18 -07:00
configure configure: fix test == usage 2016-04-09 20:05:13 -04:00
configure.ac configure: fix test == usage 2016-04-09 20:05:13 -04:00
crti.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
crtn.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
dl-irel.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
dl-lookupcfg.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
dl-machine.h Call init_cpu_features only if SHARED is defined 2016-05-13 08:29:33 -07:00
dl-procinfo.c Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
dl-procinfo.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
dl-tls.h elf: Consolidate machine-agnostic DTV definitions in <dl-dtv.h> 2016-06-20 14:31:40 +02:00
dl-tlsdesc.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
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ffs.c Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
gccframe.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
gmp-mparam.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
htonl.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
htons.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
i386-mcount.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
Implies
init-arch.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
jmpbuf-offsets.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
jmpbuf-unwind.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
ldbl2mpn.c Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
ldsodefs.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
link-defines.sym Preserve bound registers for pointer pass/return 2015-07-09 06:50:12 -07:00
lshift.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
machine-gmon.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
Makefile When disabling SSE, make sure -fpmath is not set to use SSE either 2016-04-09 22:14:24 -04:00
memchr.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
memcmp.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
memcopy.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
memcpy_chk.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
memcpy.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
memmove_chk.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
memmove.S Add i386 memset and memcpy assembly functions 2015-08-27 09:04:54 -07:00
mempcpy_chk.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
mempcpy.S Add i386 memset and memcpy assembly functions 2015-08-27 09:04:54 -07:00
memset_chk.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
memset.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
memusage.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
mp_clz_tab.c
mul_1.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
preconfigure Move base_machine and machine settings from configure.ac to sysdeps preconfigure fragments. 2014-06-25 17:52:56 +00:00
pthread_spin_trylock.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
rawmemchr.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
rshift.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
setfpucw.c Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
setjmp.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
stackguard-macros.h BZ #15754: CVE-2013-4788 2013-09-23 00:52:09 -04:00
stackinfo.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
start.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
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strchrnul.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
strcspn.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
string-inlines.c Improve generic strcspn performance 2016-04-01 10:44:40 -03:00
strlen.c Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
strlen.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
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strrchr.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
strspn.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
strtok_r.S Remove remaining bounded-pointers support from i386 .S files. 2013-02-21 22:21:52 +00:00
strtok.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
sub_n.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
submul_1.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
sysdep.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
tls-macros.h i386: Fix build by GCC 5.0 2014-12-30 11:37:41 -08:00
tlsdesc.c Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
tlsdesc.sym
tst-audit3.c Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
tst-audit3.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
tst-audit.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
tst-auditmod3a.c Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
tst-auditmod3b.c Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
tst-ld-sse-use.sh Make shebang interpreter directives consistent 2016-01-07 04:03:21 -05:00
tst-stack-align.h Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
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