On 9/3/21 3:14 AM, Tobias Burnus wrote:
If I read https://gcc.gnu.org/onlinedocs/gcc/Floating-Types.html
correctly, we should use _Float128 for the following errors
"The _Float128 type is supported on all systems where __float128 is
supported or where long double has the IEEE binary128 format."
Applies to:
For
typecodes-array-float128.f90
FAIL: gfortran.dg/c-interop/typecodes-array-float128.f90 -O0 (test
for excess errors)
Excess errors:
/gcc/testsuite/gfortran.dg/c-interop/typecodes-array-float128-c.c:35:32:
error: '__float128' undeclared (first use in this function); did you
mean '_Float128'?
typecodes-sanity.f90
FAIL: gfortran.dg/c-interop/typecodes-sanity.f90 -O0 (test for
excess errors)
Excess errors:
/gcc/testsuite/gfortran.dg/c-interop/typecodes-sanity-c.c:41:13:
error: '__float128' undeclared here (not in a function); did you mean
'_Float128'?
typecodes-scalar-float128.f90
FAIL: gfortran.dg/c-interop/typecodes-scalar-float128.f90 -O0 (test
for excess errors)
Excess errors:
/gcc/testsuite/gfortran.dg/c-interop/typecodes-scalar-float128-c.c:34:32:
error: '__float128' undeclared (first use in this function); did you
mean '_Float128'?
Just so I'm clear on this, the situation with ARM/AArch64 is that it
provides _Float128 but not __float128?
The GNU Fortran manual explicitly defines C_FLOAT128 as corresponding to
__float128, not _Float128 or some other 128-bit floating-point type.
https://gcc.gnu.org/onlinedocs/gcc-11.2.0/gfortran/ISO_005fC_005fBINDING.html#ISO_005fC_005fBINDING
So the situation with ARM/AArch64 is that it provides _Float128 but not
__float128?
I guess we could change the documentation and all the references in the
implementation as well as the test cases to tie this kind to _Float128
instead. I think that is backward-compatible with all existing uses?
* * *
PR100914.f90
FAIL: gfortran.dg/PR100914.f90 -O0 (test for excess errors)
Excess errors:
/gcc/testsuite/gfortran.dg/PR100914.c:8:10: fatal error: quadmath.h:
No such file or directory
Does ARM/Aarch64 provide _Float128 support without also providing
libquadmath.h? I'm trying to understand why it got that particular
error. :-S
* * *
On a normal x86-64 system, I get XPASS for:
gfortran.dg/PR100914.f90
gfortran.dg/c-interop/typecodes-array-float128.f90
The ! { dg-do run { xfail { { x86_64*-*-* i?86*-*-* } && longdouble128 }
} }
does not help as it just checks whether 'sizeof(long double)==16',
which seemingly passes also on x86-64 with 80bit long double.
I don't understand this, either. I've been testing on an
i686-pc-linux-gnu build with both -m32 and -m64. The tests PASS on -m32
and XFAIL on -m64. The XFAIL is there because with -m64, sizeof (long
double) == 16 and it can't be disambiguated from the true 128-bit
floating point type __float128 which also has size 16, and the other
patch I committed makes it choose the standard type over the GNU
extension type. With -m32, the 80-bit long double type has size 12
instead so there is no conflict.
-Sandra
