On Sun, May 03, 2015 at 10:59:46AM +0200, Andreas Schwab wrote:
> tbsaunde+...@tbsaunde.org writes:
>
> > +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 :0; char y; };
> > +struct foo2 { char x; int :0; char y; };
> > +int foo1test[ sizeof (struct foo1) == 2 ? 1 : -1 ];
> > +int foo2test[ sizeof (struct foo2) == 5 ? 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
> > +])
>
> gcc/config/aarch64/aarch64.h:#define PCC_BITFIELD_TYPE_MATTERS 1
>
> configure:11554: /opt/gcc/gcc-20150503/Build/./gcc/xgcc
> -B/opt/gcc/gcc-20150503/Build/./gcc/ -B/usr/aarch64-suse-linux/bin/
> -B/usr/aarch64-suse-linux/lib/ -isystem /usr/aarch64-suse-linux/include
> -isystem /usr/aarch64-suse-linux/sys-include -c -O2 -g conftest.c >&5
> conftest.c:27:5: error: size of array 'foo2test' is negative
> int foo2test[ sizeof (struct foo2) == 5 ? 1 : -1];
> ^
> configure:11554: $? = 1
ok, a quick test seems to show Jakub's version of the test works in this
case so lets try that.
Trev
>
> Andreas.
>
> --
> Andreas Schwab, sch...@linux-m68k.org
> GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
> "And now for something completely different."
