[patch, fortran] PR66461 ICE on missing end program in fixed source

[Jerry DeLisle <jvdelisle@charter.net>]

Hi all,

The following patch regression tested on x86-64.  The ICE is from an attempt to
free a bad expression after a MATCH_ERROR is returned. I have not been able to
identify an exact cause, there being numerous matchers involved attempting to
match the logical expression.

Regardless, it is an error on invalid so I suggest we commit this patch and
close the PR.  I dont think its a regression as marked in bugzilla.  I see the
the internal error as far back as 4.5.  If someone has an earlier build and can
see where this does not occur, please let me know. (In case I missed something.

The results of the patch gives the following:

$ gfc s.f
s.f:4:9:

          if ( x(1) < 0 .or.
         1
Error: Can not process after the IF statement shown at (1)
f951: Error: Unexpected end of file in ‘s.f’


OK for trunk?

Regards,

Jerry

2016-05-18  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

	PR fortran/66461
	* match.c (gfc_match_if): Catch unxpected MATCH_ERROR and issue an error
	message.


diff --git a/gcc/fortran/match.c b/gcc/fortran/match.c
index f3a4a43..85e6f92 100644
--- a/gcc/fortran/match.c
+++ b/gcc/fortran/match.c
@@ -1560,7 +1560,16 @@ gfc_match_if (gfc_statement *if_type)
   if (m == MATCH_ERROR)
     return MATCH_ERROR;

-  gfc_match (" if ( %e ) ", &expr);    /* Guaranteed to match.  */
+  m = gfc_match (" if ( %e ) ", &expr);  /* Not always guaranteed to match.  */
+
+  if (m == MATCH_ERROR)
+    {
+      /* Under some invalid conditions like unexpected end of file, one
+        can get an error in the match. We bail out here and hope for
+        the best (the best being an error reported somewhere else).  */
+      gfc_error ("Can not process after the IF statement shown at %C");
+      return MATCH_ERROR;
+    }

   m = gfc_match_pointer_assignment ();
   if (m == MATCH_YES)