OpenE2K
/
glibc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Fix default float_t definition (bug 20855). 

The default (top-level) version of bits/mathdef.h defines float_t to
double.  It is used on ColdFire, MicroBlaze, Nios II and SH3, all of
which define FLT_EVAL_METHOD to 0, so float_t should be float (and C11
requires a certain correspondence between these typedefs and
FLT_EVAL_METHOD values).

I proposed fixing this default in
<https://sourceware.org/ml/libc-alpha/2015-01/msg00499.html>, with no
objections from architecture maintainers, and this patch makes that
fix.  As noted in the NEWS entry added, this might affect the ABIs of
non-glibc libraries (ImageMagick has been mentioned in gcc-patches
discussion of the S/390 case - which is unaffected by this patch), but
as noted in my previous message, affected libraries would have
problems with -mfpmath=sse anyway on 32-bit x86.

A (compilation) testcase is added to verify the required
correspondence of typedefs to FLT_EVAL_METHOD values.  This test is
built with -fexcess-precision=standard to avoid any issues with GCC 7
on S/390 providing a more accurate FLT_EVAL_METHOD definition in the
default (no excess precision) mode.  (This will also be usable to test
a fix for the recently reported bug about these typedefs on x86_64
-mfpmath=387, as architecture-specific tests can be added that

It is entirely possible that the fixed default makes some
architecture-specific versions of bits/mathdef.h semantically
equivalent to the default version and so no longer required.  I don't
intend to investigate that separately from the refactoring I proposed
in <https://sourceware.org/ml/libc-alpha/2016-11/msg00745.html>, which
will create as few header variants as possible for each group of
definitions.

Tested (compilation only) with build-many-glibcs.py.

	[BZ #20855]
	* bits/mathdef.h (float_t): Define to float.
	* math/test-flt-eval-method.c: New file.
	* math/Makefile (tests): Add test-flt-eval-method.
	(CFLAGS-test-flt-eval-method.c): New variable.
This commit is contained in:
Joseph Myers 2016-11-23 00:28:30 +00:00
parent 510abe7b94
commit b0216d3e4d
5 changed files with 84 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
ChangeLog
View File

@ -1,3 +1,11 @@
2016-11-23 Joseph Myers <joseph@codesourcery.com>
[BZ #20855]
* bits/mathdef.h (float_t): Define to float.
* math/test-flt-eval-method.c: New file.
* math/Makefile (tests): Add test-flt-eval-method.
(CFLAGS-test-flt-eval-method.c): New variable.
2016-11-22 Steve Ellcey <sellcey@caviumnetworks.com>
* sysdeps/unix/sysv/linux/fstatfs64.c: Hide prototypes for fstatfs

5
NEWS
View File

@ -65,6 +65,11 @@ Version 2.25
- NaN functions: getpayload, getpayloadf, getpayloadl, setpayload,
setpayloadf, setpayloadl.
* On ColdFire, MicroBlaze, Nios II and SH3, the float_t type is now defined
to float instead of double. This does not affect the ABI of any libraries
that are part of the GNU C Library, but may affect the ABI of other
libraries that use this type in their interfaces.
* The functions strfromd, strfromf, and strfroml, from ISO/IEC TS 18661-1:2014,
are added to libc. They convert a floating-point number into string.

8
bits/mathdef.h
View File

@ -22,10 +22,10 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* Normally, there is no long double type and the `float' and `double'
expressions are evaluated as `double'. */
typedef double float_t; /* `float' expressions are evaluated as
`double'. */
/* Expressions are evaluated with the range and precision of their
type. */
typedef float float_t; /* `float' expressions are evaluated as
`float'. */
typedef double double_t; /* `double' expressions are evaluated as
`double'. */

3
math/Makefile
View File

@ -158,7 +158,7 @@ tests = test-matherr test-fenv atest-exp atest-sincos atest-exp2 basic-test \
test-fexcept test-fexcept-traps test-fesetexcept \
test-fesetexcept-traps test-fetestexceptflag test-femode \
test-femode-traps test-iszero-excess-precision \
test-iseqsig-excess-precision $(tests-static)
test-iseqsig-excess-precision test-flt-eval-method $(tests-static)
tests-static = test-fpucw-static test-fpucw-ieee-static \
test-signgam-uchar-static test-signgam-uchar-init-static \
test-signgam-uint-static test-signgam-uint-init-static \
@ -271,6 +271,7 @@ CFLAGS-test-math-iszero.cc = -std=gnu++11
CFLAGS-test-iszero-excess-precision.c = -fexcess-precision=standard
CFLAGS-test-iseqsig-excess-precision.c = -fexcess-precision=standard
CFLAGS-test-flt-eval-method.c = -fexcess-precision=standard
# The -lieee module sets the _LIB_VERSION_ switch to IEEE mode
# for error handling in the -lm functions.

65
math/test-flt-eval-method.c Normal file
View File

@ -0,0 +1,65 @@
/* Test evaluation method typedefs match FLT_EVAL_METHOD.
Copyright (C) 2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <float.h>
#include <math.h>
#if FLT_EVAL_METHOD == -1
/* Cannot test. */
typedef float_t my_float_t;
typedef double_t my_double_t;
#elif FLT_EVAL_METHOD == 0 || FLT_EVAL_METHOD == 16
typedef float my_float_t;
typedef double my_double_t;
#elif FLT_EVAL_METHOD == 1
typedef double my_float_t;
typedef double my_double_t;
#elif FLT_EVAL_METHOD == 2
typedef long double my_float_t;
typedef long double my_double_t;
#elif FLT_EVAL_METHOD == 32
typedef _Float32 my_float_t;
typedef double my_double_t;
#elif FLT_EVAL_METHOD == 33
typedef _Float32x my_float_t;
typedef _Float32x my_double_t;
#elif FLT_EVAL_METHOD == 64
typedef _Float64 my_float_t;
typedef _Float64 my_double_t;
#elif FLT_EVAL_METHOD == 65
typedef _Float64x my_float_t;
typedef _Float64x my_double_t;
#elif FLT_EVAL_METHOD == 128
typedef _Float128 my_float_t;
typedef _Float128 my_double_t;
#elif FLT_EVAL_METHOD == 129
typedef _Float128x my_float_t;
typedef _Float128x my_double_t;
#else
# error "Unknown FLT_EVAL_METHOD"
#endif
extern float_t test_float_t;
extern my_float_t test_float_t;
extern double_t test_double_t;
extern my_double_t test_double_t;
/* This is a compilation test. */
#define TEST_FUNCTION 0
#include "../test-skeleton.c"