https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63514
Bug ID: 63514
Summary: functions containing volatile are considered pure
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: Joost.VandeVondele at mat dot ethz.ch
The following testcase is miscompiled at -O1:
> cat test.f90
MODULE M1
CONTAINS
INTEGER FUNCTION F1()
INTEGER, VOLATILE :: i
F1=i
END FUNCTION
INTEGER FUNCTION F2()
F2=F1()+F1()
END FUNCTION
END MODULE
> gfortran -O1 -fdump-tree-optimized -fno-inline -c test.f90
;; Function f2 (__m1_MOD_f2, funcdef_no=0, decl_uid=2355, cgraph_uid=0,
symbol_order=0)
f2 ()
{
integer(kind=4) __var_1;
integer(kind=4) __result_f2.0_3;
<bb 2>:
__var_1_2 = f1 ();
__result_f2.0_3 = __var_1_2 + __var_1_2;
return __result_f2.0_3;
}
f1 should be called twice in this case, as it returns the value of a volatile.
I believe f1 is being considered as pure here, which seems not correct.
Actually, it doesn't generate an error if I add 'PURE' to the function
definition, which I assume is not correct either.
