[Bug fortran/88249] ICE in gfc_resolve_filepos, at fortran/io.c:2853

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88249

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P4
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2018-11-30
     Ever confirmed|0                           |1

--- Comment #1 from kargl at gcc dot gnu.org ---
(In reply to G. Steinmetz from comment #0)
> With a missing file-unit-number, down to at least gcc-5 :
> 
> 
> $ cat z1.f90
> program p
>    backspace (err=1)
>    endfile (err=1)
>    flush (err=1)
>    rewind (err=1)
> end
> 
> 
> $ gfortran-9-20181125 -c z1.f90
> f951: internal compiler error: Segmentation fault
> 0xb2bcff crash_signal
>         ../../gcc/toplev.c:326
> 0x63f696 gfc_resolve_filepos(gfc_filepos*)
>         ../../gcc/fortran/io.c:2853
> 0x6850ab gfc_resolve_code(gfc_code*, gfc_namespace*)
>         ../../gcc/fortran/resolve.c:11547
> 0x68702f resolve_codes


Index: gcc/fortran/resolve.c
===================================================================
--- gcc/fortran/resolve.c       (revision 266386)
+++ gcc/fortran/resolve.c       (working copy)
@@ -11544,7 +11544,7 @@ start:
        case EXEC_ENDFILE:
        case EXEC_REWIND:
        case EXEC_FLUSH:
-         if (!gfc_resolve_filepos (code->ext.filepos))
+         if (!gfc_resolve_filepos (code->ext.filepos, &code->loc))
            break;

          resolve_branch (code->ext.filepos->err, code);
Index: gcc/fortran/io.c
===================================================================
--- gcc/fortran/io.c    (revision 266386)
+++ gcc/fortran/io.c    (working copy)
@@ -2834,22 +2834,21 @@ cleanup:


 bool
-gfc_resolve_filepos (gfc_filepos *fp)
+gfc_resolve_filepos (gfc_filepos *fp, locus *where)
 {
   RESOLVE_TAG (&tag_unit, fp->unit);
   RESOLVE_TAG (&tag_iostat, fp->iostat);
   RESOLVE_TAG (&tag_iomsg, fp->iomsg);
-  if (!gfc_reference_st_label (fp->err, ST_LABEL_TARGET))
-    return false;

-  if (!fp->unit && (fp->iostat || fp->iomsg))
+  if (!fp->unit && (fp->iostat || fp->iomsg || fp->err))
     {
-      locus where;
-      where = fp->iostat ? fp->iostat->where : fp->iomsg->where;
-      gfc_error ("UNIT number missing in statement at %L", &where);
+      gfc_error ("UNIT number missing in statement at %L", where);
       return false;
     }

+  if (!gfc_reference_st_label (fp->err, ST_LABEL_TARGET))
+    return false;
+
   if (fp->unit->expr_type == EXPR_CONSTANT
       && fp->unit->ts.type == BT_INTEGER
       && mpz_sgn (fp->unit->value.integer) < 0)