1 files changed, 85 insertions, 0 deletions
diff --git a/test/Sema/empty1.c b/test/Sema/empty1.c
new file mode 100644
index 0000000..de922f7
--- /dev/null
+++ b/test/Sema/empty1.c
@@ -0,0 +1,85 @@
+// RUN: %clang_cc1 %s -fsyntax-only -verify -Wc++-compat
+
+struct emp_1 { // expected-warning {{empty struct has size 0 in C, size 1 in C++}}
+};
+
+union emp_2 { // expected-warning {{empty union has size 0 in C, size 1 in C++}}
+};
+
+struct emp_3 { // expected-warning {{struct has size 0 in C, size 1 in C++}}
+  int : 0;
+};
+
+union emp_4 { // expected-warning {{union has size 0 in C, size 1 in C++}}
+  int : 0;
+};
+
+struct emp_5 { // expected-warning {{struct has size 0 in C, size 1 in C++}}
+  int : 0;
+  int : 0;
+};
+
+union emp_6 { // expected-warning {{union has size 0 in C, size 1 in C++}}
+  int : 0;
+  int : 0;
+};
+
+struct emp_7 { // expected-warning {{struct has size 0 in C, size 1 in C++}}
+  struct emp_1 f1;
+};
+
+union emp_8 { // expected-warning {{union has size 0 in C, size 1 in C++}}
+  struct emp_1 f1;
+};
+
+struct emp_9 { // expected-warning {{struct has size 0 in C, non-zero size in C++}}
+  struct emp_1 f1;
+  union emp_2 f2;
+};
+
+// Checks for pointer subtraction (PR15683)
+struct emp_1 *func_1p(struct emp_1 *x) { return x - 5; }
+
+int func_1() {
+  struct emp_1 v[1];
+  return v - v; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}}
+}
+
+int func_2(struct emp_1 *x) {
+  return 1 + x - x; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}}
+}
+
+int func_3(struct emp_1 *x, struct emp_1 *y) {
+  return x - y; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}}
+}
+
+int func_4(struct emp_1 *x, const struct emp_1 *y) {
+  return x - y; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}}
+}
+
+int func_5(volatile struct emp_1 *x, const struct emp_1 *y) {
+  return x - y; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}}
+}
+
+int func_6() {
+  union emp_2 v[1];
+  return v - v; // expected-warning {{subtraction of pointers to type 'union emp_2' of zero size has undefined behavior}}
+}
+
+struct A; // expected-note {{forward declaration of 'struct A'}}
+
+int func_7(struct A *x, struct A *y) {
+  return x - y; // expected-error {{arithmetic on a pointer to an incomplete type 'struct A'}}
+}
+
+int func_8(struct emp_1 (*x)[10], struct emp_1 (*y)[10]) {
+  return x - y; // expected-warning {{subtraction of pointers to type 'struct emp_1 [10]' of zero size has undefined behavior}}
+}
+
+int func_9(struct emp_1 (*x)[], struct emp_1 (*y)[]) {
+  return x - y; // expected-error {{arithmetic on a pointer to an incomplete type 'struct emp_1 []'}}
+}
+
+int func_10(int (*x)[0], int (*y)[0]) {
+  return x - y; // expected-warning {{subtraction of pointers to type 'int [0]' of zero size has undefined behavior}}
+}