On Fri, Mar 09, 2018 at 09:13:10PM -0800, Steve Kargl wrote:
> In fixing PR fortran/83633, it seems the patch I committed
> introduced an ICE for nonsensical invalid Fortran. The
> attached patch cures the ICE and now (re)issues an error
> message.
>
> The basic problem seems to boil down to the recursive
> calling of gfc_simplify_expr reduces "huge(1_8)+1_8" to
> "constant + constant". When the chain of gfc_simplify_expr
> tries to reduces this expression an overflow occurs. An
> error message is queud but never emitted, and the result
> is set to NULL and both constants are freed. The NULL is
> passed back up through the chain of gfc_simplify_expr.
> At some point that NULL pointer is referenced. The patch
> works around the problem by passing the result with the
> overflow value up the chain.
>
> Regression tested on x86_64-*-freebsd. I intend to commit
> this patch tomorrow, which on my clock is only 2.75 hours
> away.
>
> 2018-03-09 Steven G. Kargl <ka...@gcc.gnu.org>
>
> PR fortran/84734
> * arith.c (check_result, eval_intrinsic): If result overflows, pass
> the expression up the chain instead of a NULL pointer.
>
> 2018-03-09 Steven G. Kargl <ka...@gcc.gnu.org>
>
> PR fortran/84734
> * gfortran.dg/pr84734.f90: New test.
>
Now with an attached patch.
--
Steve
Index: gcc/fortran/arith.c
===================================================================
--- gcc/fortran/arith.c (revision 258367)
+++ gcc/fortran/arith.c (working copy)
@@ -555,10 +555,10 @@ check_result (arith rc, gfc_expr *x, gfc_expr *r, gfc_
val = ARITH_OK;
}
- if (val != ARITH_OK)
- gfc_free_expr (r);
- else
+ if (val == ARITH_OK || val == ARITH_OVERFLOW)
*rp = r;
+ else
+ gfc_free_expr (r);
return val;
}
@@ -1603,8 +1603,12 @@ eval_intrinsic (gfc_intrinsic_op op,
if (rc != ARITH_OK)
{
gfc_error (gfc_arith_error (rc), &op1->where);
+ if (rc == ARITH_OVERFLOW)
+ goto done;
return NULL;
}
+
+done:
gfc_free_expr (op1);
gfc_free_expr (op2);
Index: gcc/testsuite/gfortran.dg/pr84734.f90
===================================================================
--- gcc/testsuite/gfortran.dg/pr84734.f90 (nonexistent)
+++ gcc/testsuite/gfortran.dg/pr84734.f90 (working copy)
@@ -0,0 +1,4 @@
+! { dg-do compile }
+! PR fortran/84734
+ integer :: b(huge(1_8)+1_8) = 0 ! { dg-error "Arithmetic overflow" }
+ end
