gcc/config/bitfields.m4
Trevor Saunders d6ed95fcb5 Improve the test in bitfields.m4
Using a named bitfield with a width more than 0 means we won't hit
weirdness caused by the bitfield not really needing to exist.  Changing
int to long long means we won't have trouble with some arch where size
of int is 1 or 2.

libobjc/ChangeLog:

2015-05-04  Trevor Saunders  <tbsaunde+gcc@tbsaunde.org>

	* configure: Regenerate.

config/ChangeLog:

2015-05-04  Trevor Saunders  <tbsaunde+gcc@tbsaunde.org>

	* bitfields.m4: Change int to long long, and use bitfields of
	width 1 instead of 0.

From-SVN: r222794
2015-05-05 03:41:53 +00:00

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dnl Copyright (C) 2015 Free Software Foundation, Inc.
dnl This file is free software, distributed under the terms of the GNU
dnl General Public License. As a special exception to the GNU General
dnl Public License, this file may be distributed as part of a program
dnl that contains a configuration script generated by Autoconf, under
dnl the same distribution terms as the rest of that program.
# Define HAVE_BITFIELD_TYPE_MATTERS if the type of bitfields effects their
# alignment.
AC_DEFUN([gt_BITFIELD_TYPE_MATTERS],
[
AC_CACHE_CHECK([if the type of bitfields matters], gt_cv_bitfield_type_matters,
[
AC_TRY_COMPILE(
[struct foo1 { char x; char y:1; char z; };
struct foo2 { char x; long long int y:1; char z; };
int foo1test[ sizeof (struct foo1) < sizeof (struct foo2) ? 1 : -1 ]; ],
[], gt_cv_bitfield_type_matters=yes, gt_cv_bitfield_type_matters=no)
])
if test $gt_cv_bitfield_type_matters = yes; then
AC_DEFINE(HAVE_BITFIELD_TYPE_MATTERS, 1,
[Define if the type of bitfields effects alignment.])
fi
])