glibc

Tree: e6b4e2de6d

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Author	SHA1	Message	Date
Joseph Myers	bfff8b1bec	Update copyright dates with scripts/update-copyrights.	9 years ago
Joseph Myers	93eb85ceb2	Refactor float_t, double_t information into bits/flt-eval-method.h. At present, definitions of float_t and double_t are split among many bits/mathdef.h headers. For all but three architectures, these types are float and double. Furthermore, if you assume __FLT_EVAL_METHOD__ to be defined, that provides a more generic way of determining the correct values of these typedefs. Defining these typedefs more generally based on __FLT_EVAL_METHOD__ was previously proposed by Paul Eggert in <https://sourceware.org/ml/libc-alpha/2012-02/msg00002.html>. This patch refactors things in the way I proposed in <https://sourceware.org/ml/libc-alpha/2016-11/msg00745.html>. A new header bits/flt-eval-method.h defines a single macro, __GLIBC_FLT_EVAL_METHOD, which is then used by math.h to define float_t and double_t. The default is based on __FLT_EVAL_METHOD__ (although actually a default to 0 would have the same effect for current ports, because ports where values other than 0 or 16 are possible all have their own headers). To avoid changing the existing semantics in any case, including for compilers not defining __FLT_EVAL_METHOD__, architecture-specific files are then added for m68k, s390, x86 which replicate the existing semantics. At least with __FLT_EVAL_METHOD__ values possible with GCC, there should be no change to the choices of float_t and double_t for any supported configuration. Architecture maintainer notes: * m68k: sysdeps/m68k/m680x0/bits/flt-eval-method.h always defines __GLIBC_FLT_EVAL_METHOD to 2 to replicate the existing logic. But actually GCC defines __FLT_EVAL_METHOD__ to 0 if TARGET_68040. It might make sense to make the header prefer to base things on __FLT_EVAL_METHOD__ if defined, like the x86 version, and so make the choices of these types more accurate (with a NEWS entry as for the other changes to these types on particular architectures). * s390: sysdeps/s390/bits/flt-eval-method.h always defines __GLIBC_FLT_EVAL_METHOD to 1 to replicate the existing logic. As previously discussed, it might make sense in coordination with GCC to eliminate the historic mistake, avoid excess precision in the -fexcess-precision=standard case and make the typedefs match (with a NEWS entry, again). Tested for x86-64 and x86. Also did compilation-only testing with build-many-glibcs.py. * bits/flt-eval-method.h: New file. * sysdeps/m68k/m680x0/bits/flt-eval-method.h: Likewise. * sysdeps/s390/bits/flt-eval-method.h: Likewise. * sysdeps/x86/bits/flt-eval-method.h: Likewise. * math/Makefile (headers): Add bits/flt-eval-method.h. * math/math.h: Include <bits/flt-eval-method.h>. [__USE_ISOC99] (float_t): Define based on __GLIBC_FLT_EVAL_METHOD. [__USE_ISOC99] (double_t): Likewise. * bits/mathdef.h (float_t): Remove. (double_t): Likewise. * sysdeps/aarch64/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/alpha/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/arm/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/hppa/fpu/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/ia64/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/m68k/m680x0/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/mips/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/powerpc/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/s390/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/sh/sh4/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/sparc/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/tile/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/x86/bits/mathdef.h (float_t): Likewise. (double_t): Likewise.	10 years ago

Author

SHA1

Message

Date

Joseph Myers

bfff8b1bec

Update copyright dates with scripts/update-copyrights.

9 years ago

Joseph Myers

93eb85ceb2

Refactor float_t, double_t information into bits/flt-eval-method.h.

At present, definitions of float_t and double_t are split among many
bits/mathdef.h headers.

For all but three architectures, these types are float and double.
Furthermore, if you assume __FLT_EVAL_METHOD__ to be defined, that
provides a more generic way of determining the correct values of these
typedefs.  Defining these typedefs more generally based on
__FLT_EVAL_METHOD__ was previously proposed by Paul Eggert in
<https://sourceware.org/ml/libc-alpha/2012-02/msg00002.html>.

This patch refactors things in the way I proposed in
<https://sourceware.org/ml/libc-alpha/2016-11/msg00745.html>.  A new
header bits/flt-eval-method.h defines a single macro,
__GLIBC_FLT_EVAL_METHOD, which is then used by math.h to define
float_t and double_t.  The default is based on __FLT_EVAL_METHOD__
(although actually a default to 0 would have the same effect for
current ports, because ports where values other than 0 or 16 are
possible all have their own headers).

To avoid changing the existing semantics in any case, including for
compilers not defining __FLT_EVAL_METHOD__, architecture-specific
files are then added for m68k, s390, x86 which replicate the existing
semantics.  At least with __FLT_EVAL_METHOD__ values possible with
GCC, there should be no change to the choices of float_t and double_t
for any supported configuration.

Architecture maintainer notes:

* m68k: sysdeps/m68k/m680x0/bits/flt-eval-method.h always defines
  __GLIBC_FLT_EVAL_METHOD to 2 to replicate the existing logic.  But
  actually GCC defines __FLT_EVAL_METHOD__ to 0 if TARGET_68040.  It
  might make sense to make the header prefer to base things on
  __FLT_EVAL_METHOD__ if defined, like the x86 version, and so make
  the choices of these types more accurate (with a NEWS entry as for
  the other changes to these types on particular architectures).

* s390: sysdeps/s390/bits/flt-eval-method.h always defines
  __GLIBC_FLT_EVAL_METHOD to 1 to replicate the existing logic.  As
  previously discussed, it might make sense in coordination with GCC
  to eliminate the historic mistake, avoid excess precision in the
  -fexcess-precision=standard case and make the typedefs match (with a
  NEWS entry, again).

Tested for x86-64 and x86.  Also did compilation-only testing with
build-many-glibcs.py.

	* bits/flt-eval-method.h: New file.
	* sysdeps/m68k/m680x0/bits/flt-eval-method.h: Likewise.
	* sysdeps/s390/bits/flt-eval-method.h: Likewise.
	* sysdeps/x86/bits/flt-eval-method.h: Likewise.
	* math/Makefile (headers): Add bits/flt-eval-method.h.
	* math/math.h: Include <bits/flt-eval-method.h>.
	[__USE_ISOC99] (float_t): Define based on __GLIBC_FLT_EVAL_METHOD.
	[__USE_ISOC99] (double_t): Likewise.
	* bits/mathdef.h (float_t): Remove.
	(double_t): Likewise.
	* sysdeps/aarch64/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/alpha/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/arm/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/hppa/fpu/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/ia64/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/m68k/m680x0/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/mips/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/powerpc/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/s390/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/sh/sh4/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/sparc/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/tile/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/x86/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.

10 years ago

2 Commits (e6b4e2de6dd91efdcac80b79149c596de8a26b70)