The spaghetti code in PR fortran/91359 has a few gotos
to jump to different places. In doing so, gfortran
with generate a function that has a naked 'return'.
Namely,
foo ()
{
logical(kind=4) __result_foo;
goto __label_000002;
__label_000001:;
return; /* <-- THIS IS BAD. */
__label_000002:;
__result_foo = 0;
if (!__result_foo) goto __label_000001;
L.1:;
return __result_foo;
return __result_foo;
}
The attached patch avoids the naked 'return' by
adding the variable that is constructed from the
the function name. Namely,
foo ()
{
logical(kind=4) __result_foo;
goto __label_000002;
__label_000001:;
return __result_foo; /* <-- THIS IS GOOD. */
__label_000002:;
__result_foo = 0;
if (!__result_foo) goto __label_000001;
L.1:;
return __result_foo;
return __result_foo;
}
Regression tested on x86_64-*-freebsd. OK to commit?
2019-08-06 Steven G. Kargl <ka...@gcc.gnu.org>
PR fortran/91359
* trans-decl.c (gfc_generate_return): Ensure something is returned
from a function.
2019-08-06 Steven G. Kargl <ka...@gcc.gnu.org>
PR fortran/91359
* gfortran.dg/pr91359_1.f: New test.
* gfortran.dg/pr91359_2.f: Ditto.
--
Steve
Index: gcc/fortran/trans-decl.c
===================================================================
--- gcc/fortran/trans-decl.c (revision 274121)
+++ gcc/fortran/trans-decl.c (working copy)
@@ -6449,6 +6449,20 @@ gfc_generate_return (void)
TREE_TYPE (result), DECL_RESULT (fndecl),
result);
}
+ else
+ {
+ /* If the function does not have a result variable, result is
+ NULL_TREE, and a 'return' is generated without a variable.
+ The following generates a 'return __result_XXX' where XXX is
+ the function name. */
+ if (sym == sym->result && sym->attr.function)
+ {
+ result = gfc_get_fake_result_decl (sym, 0);
+ result = fold_build2_loc (input_location, MODIFY_EXPR,
+ TREE_TYPE (result),
+ DECL_RESULT (fndecl), result);
+ }
+ }
}
return build1_v (RETURN_EXPR, result);
Index: gcc/testsuite/gfortran.dg/pr91359_1.f
===================================================================
--- gcc/testsuite/gfortran.dg/pr91359_1.f (nonexistent)
+++ gcc/testsuite/gfortran.dg/pr91359_1.f (working copy)
@@ -0,0 +1,17 @@
+! { dg do }
+! PR fortran/91359
+! Orginal code contributed by Brian T. Carcich <briantcarcich at gmail dot com>
+!
+ logical function zero() result(a)
+ goto 2
+1 return
+2 a = .false.
+ if (.not.a) goto 1
+ return
+ end
+
+ program test_zero
+ logical zero
+ if (zero()) stop 'FAIL: zero() returned .TRUE.'
+ stop 'OKAY: zero() returned .FALSE.'
+ end
Index: gcc/testsuite/gfortran.dg/pr91359_2.f
===================================================================
--- gcc/testsuite/gfortran.dg/pr91359_2.f (nonexistent)
+++ gcc/testsuite/gfortran.dg/pr91359_2.f (working copy)
@@ -0,0 +1,17 @@
+! { dg do }
+! PR fortran/91359
+! Orginal code contributed by Brian T. Carcich <briantcarcich at gmail dot com>
+!
+ logical function zero() result(a)
+ goto 2
+1 return
+2 a = .false.
+ if (.not.a) goto 1
+ return
+ end
+
+ program test_zero
+ logical zero
+ if (zero()) stop 'FAIL: zero() returned .TRUE.'
+ stop 'OKAY: zero() returned .FALSE.'
+ end
