mirror of
git://sourceware.org/git/glibc.git
synced 2025-02-23 13:09:58 +08:00
c0b4353654
TS 18661-1 defines a macro FE_SNANS_ALWAYS_SIGNAL in <fenv.h>, to indicate that the recommended practice regarding sNaNs (that operations always produce a qNaN output with "invalid" exception, even in the fmax / fmin / hypot / pow cases where a qNaN input would not result in qNaN output) is followed. Now that those functions with C99 special cases for NaNs have been fixed not to apply those special cases to sNaN, only to qNaN, glibc follows that recommended practice. This patch makes it define the corresponding macro. Since compiler optimizations may affect whether sNaNs behave as expected and the macro relates to both language and library features, it is only defined if __SUPPORT_SNAN__ is defined (which GCC defines for -fsignaling-nans). It is also not defined if FE_INVALID is undefined, since the recommended practice specifically refers to raising the "invalid" exception, so it seems inappropriate to define the macro for soft-float cases without support for exceptions. (Further refinement would be possible in cases where bits/fenv.h is shared by configurations both with and without exceptions support.) Tested for x86_64 and x86, and also did compile-only testing for nios2 to cover the no-exceptions case. * math/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT) && FE_INVALID && __SUPPORT_SNAN__] (FE_SNANS_ALWAYS_SIGNAL): New macro. * math/test-fe-snans-always-signal.c: New file. * math/Makefile (tests): Add test-fe-snans-always-signal. (CFLAGS-test-fe-snans-always-signal.c): New variable. * manual/arith.texi (Infinity and NaN): Document FE_SNANS_ALWAYS_SIGNAL. |
||
|---|---|---|
| .. | ||
| examples | ||
| argp.texi | ||
| arith.texi | ||
| charset.texi | ||
| check-safety.sh | ||
| conf.texi | ||
| contrib.texi | ||
| creature.texi | ||
| crypt.texi | ||
| ctype.texi | ||
| debug.texi | ||
| dir | ||
| errno.texi | ||
| fdl-1.3.texi | ||
| filesys.texi | ||
| freemanuals.texi | ||
| getopt.texi | ||
| header.texi | ||
| install-plain.texi | ||
| install.texi | ||
| intro.texi | ||
| io.texi | ||
| ipc.texi | ||
| job.texi | ||
| lang.texi | ||
| lgpl-2.1.texi | ||
| libc-texinfo.sh | ||
| libc.texinfo | ||
| libcbook.texi | ||
| libdl.texi | ||
| libm-err-tab.pl | ||
| llio.texi | ||
| locale.texi | ||
| macros.texi | ||
| maint.texi | ||
| Makefile | ||
| math.texi | ||
| memory.texi | ||
| message.texi | ||
| nss.texi | ||
| nsswitch.texi | ||
| pattern.texi | ||
| pipe.texi | ||
| platform.texi | ||
| probes.texi | ||
| process.texi | ||
| resource.texi | ||
| search.texi | ||
| setjmp.texi | ||
| signal.texi | ||
| socket.texi | ||
| startup.texi | ||
| stdio-fp.c | ||
| stdio.texi | ||
| string.texi | ||
| summary.awk | ||
| sysinfo.texi | ||
| syslog.texi | ||
| terminal.texi | ||
| texinfo.tex | ||
| texis.awk | ||
| threads.texi | ||
| time.texi | ||
| tsort.awk | ||
| users.texi | ||
| xtract-typefun.awk | ||