Fortran: fix NULL pointer dereference in gfc_check_dependency [PR108502]

gcc/fortran/ChangeLog:

	PR fortran/108502
	* dependency.cc (gfc_check_dependency): Prevent NULL pointer
	dereference while recursively checking expressions.

gcc/testsuite/ChangeLog:

	PR fortran/108502
	* gfortran.dg/pr108502.f90: New test.

(cherry picked from commit 51767f31878a95161142254dca7119b409699670)

diff --git a/gcc/fortran/dependency.cc b/gcc/fortran/dependency.cc
index ab3bd36f74ed143ce8e7918919674002e4480591..3aa696cefe62df88214ea2d21bc76c048ec6a74d 100644 (file)
--- a/gcc/fortran/dependency.cc
+++ b/gcc/fortran/dependency.cc
@@ -1292,6 +1292,11 @@ gfc_check_dependency (gfc_expr *expr1, gfc_expr *expr2, bool identical)
   if (expr1->expr_type != EXPR_VARIABLE)
     gfc_internal_error ("gfc_check_dependency: expecting an EXPR_VARIABLE");
 
+  /* Prevent NULL pointer dereference while recursively analyzing invalid
+     expressions.  */
+  if (expr2 == NULL)
+    return 0;
+
   switch (expr2->expr_type)
     {
     case EXPR_OP:

diff --git a/gcc/testsuite/gfortran.dg/pr108502.f90 b/gcc/testsuite/gfortran.dg/pr108502.f90
new file mode 100644 (file)
index 0000000..45f7384
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr108502.f90
@@ -0,0 +1,12 @@
+! { dg-do compile }
+! { dg-options "-O2 -ffrontend-optimize" }
+! PR fortran/108502 - ICE in gfc_check_dependency
+! Contributed by G.Steinmetz
+
+integer function n()
+  integer :: a(1)
+  a = [1] / 0
+end
+program p
+  integer :: b = n() ! { dg-error "must be an intrinsic function" }
+end