[Bug fortran/38907] [4.3/4.4 Regression ] ICE when contained function has same name as module function and used in expression

["burnus at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #3 from burnus at gcc dot gnu dot org  2009-01-18 22:27 -------
Confirm. Thanks for the report!

Valgrind shows:

==20941== Conditional jump or move depends on uninitialised value(s)
==20941==    at 0x46C602: gfc_resolve_expr (resolve.c:4353)
==20941==    by 0x46BC22: gfc_resolve_expr (resolve.c:3057)
==20941==    by 0x472944: resolve_code (resolve.c:6676)

==20941== Use of uninitialised value of size 8
==20941==    at 0x46C608: gfc_resolve_expr (resolve.c:4353)

==20941== Invalid read of size 8
==20941==    at 0x46C608: gfc_resolve_expr (resolve.c:4353)

That line is:

  4349            gfc_match_rvalue (&expr);
  4350            gfc_clear_error ();
  4351            gfc_buffer_error (0);
  4352
  4353            gcc_assert (expr && sym == expr->symtree->n.sym);

I added some debug printfs and valgrind shows invalid reads for:
  expr == NULL
and
  expr->symtree
where the latter results in a segfault.

I think the problem occurs if gfc_match_rvalue does not match. Then the
argument "&expr" will remain unmodified.

If one applies the following patch, the compilation will fail with the bogus
error

          RDA(1,2) = + S_REAL_SUM_I(1.0,2.0)
                                   1
Error: Unclassifiable statement at (1)


--- resolve.c   (Revision 143486)
+++ resolve.c
@@ -4348,3 +4348,4 @@ check_host_association (gfc_expr *e)
    only integers and vectors can be involved.  */
-         gfc_match_rvalue (&expr);
+         if (gfc_match_rvalue (&expr) == MATCH_YES)
+           {
          gfc_clear_error ();
@@ -4359,2 +4360,3 @@ check_host_association (gfc_expr *e)
          gfc_current_locus = temp_locus;
+           }
        }


-- 

burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
OtherBugsDependingO|                            |32834
              nThis|                            |
           Keywords|                            |ice-on-valid-code
      Known to work|4.2.5                       |4.2.5 4.3.1
            Summary|[regression 4.3/4.4] ICE    |[4.3/4.4 Regression ] ICE
                   |when contained function has |when contained function has
                   |same name as module function|same name as module function
                   |and used in expression      |and used in expression
   Target Milestone|---                         |4.3.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38907