tree-optimization/117060 - fix oversight in vect_build_slp_tree_1

We are failing to match call vs. non-call when dealing with matching
loads or stores.

	PR tree-optimization/117060
	* tree-vect-slp.cc (vect_build_slp_tree_1): When comparing
	calls also fail if the first isn't a call.

	* gfortran.dg/pr117060.f90: New testcase.

gcc/testsuite/gfortran.dg/pr117060.f90

@@ -0,0 +1,21 @@
+! { dg-do compile }
+! { dg-options "-O2" }
+
+subroutine foo (out)
+
+implicit none
+
+real    :: out(*)
+integer :: i,k
+real    :: a(100)
+real    :: b(100)
+
+k = 0
+do i = 1, 10
+  k = k + 1
+  out(k) = a(i)
+  k = k + 1
+  out(k) = sqrt((a(3*i)-b(4))**2 + (a(3*i+1)-b(4+1))**2)
+end do
+
+end subroutine

gcc/tree-vect-slp.cc

@@ -1367,8 +1367,9 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
 	      && first_stmt_code != CFN_MASK_LOAD
 	      && first_stmt_code != CFN_MASK_STORE)
 	    {
-	      if (!compatible_calls_p (as_a <gcall *> (stmts[0]->stmt),
-				       call_stmt))
+	      if (!is_a <gcall *> (stmts[0]->stmt)
+		  || !compatible_calls_p (as_a <gcall *> (stmts[0]->stmt),
+					  call_stmt))
 		{
 		  if (dump_enabled_p ())
 		    dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,