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Created attachment 1192960[details]
reproducer.tar
This is a simple crash on apparently valid code. The
crash happens due to no fields declared to a sequence
type; adding a field or removing the sequence attribute
prevents the crash.
A simple patch could be to add:
if (dt1 == dt2)
return 1;
if (!dt1 || !dt2)
return 0;
to gfc_compare_derived_types before the for loop:
389 int
390 gfc_compare_derived_types (gfc_symbol *derived1, gfc_symbol *derived2)
[...]
421 dt1 = derived1->components;
422 dt2 = derived2->components;
423
424 /* Since subtypes of SEQUENCE types must be SEQUENCE types as well, a
425 simple test can speed things up. Otherwise, lots of things have to
426 match. */
427 for (;;)
428 {
429 if (strcmp (dt1->name, dt2->name) != 0)
430 return 0;
431
432 if (dt1->attr.access != dt2->attr.access)
433 return 0;
or a slightly less readable variant:
if (!dt1 || !dt2)
return dt1 == dt2;
Simple reproducer derived from user issue attached.
The ICE was fixed in <https://gcc.gnu.org/r235999>. But since that revision I get:
$ ./f951 -quiet t.f90
t.f90:6:12:
call sub(tst)
1
Error: Type mismatch in argument ‘test’ at (1); passed TYPE(test_t) to TYPE(test_t)
You said "apparently valid code", but did you really mean "valid"? I don't know Fortran to gauge whether this is or isn't valid.
In any case, the revision is pretty recent and doesn't seem to be backportable.
I said apparently valid code because the specification
appears to not tell about empty types:
TYPE [[ , access specification ] :: ] type name
[ PRIVATE ]
[ SEQUENCE ]
[ type specification [[ , POINTER ] :: ] component specification list ]
...
END TYPE [ type name ]
The type mismatch error is expected. The user just
believes that the ICE should not happen.
Sure, the ICE is definitely a bug, but if the type mismatch error is expected, then this would be ICE-on-invalid, and such bugs have a rather low priority.
I just tested on rawhide, with this minor change,
to make the types compatible:
mod.f90:
- integer(4) type
+! integer(4) type
and test.sh (to avoid link failure):
- gfortran t.f90
+ gfortran -c t.f90
and it compiles and generates .o files.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHBA-2017:2094
Created attachment 1192960 [details] reproducer.tar This is a simple crash on apparently valid code. The crash happens due to no fields declared to a sequence type; adding a field or removing the sequence attribute prevents the crash. A simple patch could be to add: if (dt1 == dt2) return 1; if (!dt1 || !dt2) return 0; to gfc_compare_derived_types before the for loop: 389 int 390 gfc_compare_derived_types (gfc_symbol *derived1, gfc_symbol *derived2) [...] 421 dt1 = derived1->components; 422 dt2 = derived2->components; 423 424 /* Since subtypes of SEQUENCE types must be SEQUENCE types as well, a 425 simple test can speed things up. Otherwise, lots of things have to 426 match. */ 427 for (;;) 428 { 429 if (strcmp (dt1->name, dt2->name) != 0) 430 return 0; 431 432 if (dt1->attr.access != dt2->attr.access) 433 return 0; or a slightly less readable variant: if (!dt1 || !dt2) return dt1 == dt2; Simple reproducer derived from user issue attached.