PR fortran/93499 - ICE on division by zero in declaration statements

Division by zero in declaration statements could sometimes
generate NULL pointers being passed around that lead to ICEs.

2020-05-10  Harald Anlauf  <anlauf@gmx.de>

gcc/fortran/
	PR fortran/93499
	* arith.c (gfc_divide): Catch division by zero.
	(eval_intrinsic_f3): Safeguard for NULL operands.

gcc/testsuite/
	PR fortran/93499
	* gfortran.dg/pr93499.f90: New test.

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index beeabfa..6f1db38 100644 (file)
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,9 @@
+2020-05-10  Harald Anlauf  <anlauf@gmx.de>
+
+       PR fortran/93499
+       * arith.c (gfc_divide): Catch division by zero.
+       (eval_intrinsic_f3): Safeguard for NULL operands.
+
 2020-05-05  Steve Kargl  <kargl@gcc.gnu.org>
        Harald Anlauf  <anlauf@gmx.de>
 

diff --git a/gcc/fortran/arith.c b/gcc/fortran/arith.c
index 422ef40..1cd0867 100644 (file)
--- a/gcc/fortran/arith.c
+++ b/gcc/fortran/arith.c
@@ -1746,6 +1746,9 @@ eval_intrinsic_f3 (gfc_intrinsic_op op,
   gfc_expr *result;
   eval_f f;
 
+  if (!op1 && !op2)
+    return NULL;
+
   result = reduce_binary0 (op1, op2);
   if (result != NULL)
     return eval_type_intrinsic0(op, result);
@@ -1803,6 +1806,37 @@ gfc_multiply (gfc_expr *op1, gfc_expr *op2)
 gfc_expr *
 gfc_divide (gfc_expr *op1, gfc_expr *op2)
 {
+  if (op2 && op2->expr_type == EXPR_CONSTANT)
+    {
+      arith rc = ARITH_OK;
+      switch (op2->ts.type)
+       {
+       case BT_INTEGER:
+         /* non-integer divided by integer 0 is handled elsewhere.  */
+         if (mpz_sgn (op2->value.integer) == 0
+             && op1->ts.type == BT_INTEGER)
+           rc = ARITH_DIV0;
+         break;
+       case BT_REAL:
+         if (mpfr_sgn (op2->value.real) == 0
+             && flag_range_check == 1)
+           rc = ARITH_DIV0;
+         break;
+       case BT_COMPLEX:
+         if (mpc_cmp_si_si (op2->value.complex, 0, 0) == 0
+             && flag_range_check == 1)
+           rc = ARITH_DIV0;
+         break;
+       default:
+         gfc_internal_error ("gfc_divide(): Bad basic type");
+       }
+      if (rc == ARITH_DIV0)
+       {
+         gfc_seen_div0 = true;
+         gfc_error ("Division by zero at %L", &op2->where);
+         return NULL;
+       }
+    }
   return eval_intrinsic_f3 (INTRINSIC_DIVIDE, gfc_arith_divide, op1, op2);
 }
 

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9deb7ac..791c62a 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-05-10  Harald Anlauf  <anlauf@gmx.de>
+
+       PR fortran/93499
+       * gfortran.dg/pr93499.f90: New test.
+
 2020-05-09  Jakub Jelinek  <jakub@redhat.com>
 
        PR testsuite/95008

diff --git a/gcc/testsuite/gfortran.dg/pr93499.f90 b/gcc/testsuite/gfortran.dg/pr93499.f90
new file mode 100644 (file)
index 0000000..7a414bb
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr93499.f90
@@ -0,0 +1,10 @@
+! { dg-do compile }
+! PR 93499 - this used to ICE. Original test case by Gerhard Steinmetz.
+
+program p
+  integer :: a((0.)/0)  ! { dg-error "Division by zero" }
+  type t(n)
+     integer, len :: n
+  end type t
+  type(t((0)/0))  :: x  ! { dg-error "Division by zero" }
+end