--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/Sema/rounding-math.c	Tue Jun 08 06:07:14 2021 +0900
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -triple x86_64-linux -std=c17 -verify=expected,norounding %s
+// RUN: %clang_cc1 -triple x86_64-linux -std=gnu17 -verify=expected,norounding %s
+// RUN: %clang_cc1 -triple x86_64-linux -std=c17 -verify=expected,rounding %s -frounding-math
+// RUN: %clang_cc1 -triple x86_64-linux -std=gnu17 -verify=expected,rounding %s -frounding-math
+
+#define fold(x) (__builtin_constant_p(x) ? (x) : (x))
+
+double a = 1.0 / 3.0;
+
+#define f(n) ((n) * (1.0 / 3.0))
+_Static_assert(fold((int)f(3)) == 1, "");
+
+typedef int T[fold((int)f(3))];
+typedef int T[1];
+
+enum Enum { enum_a = (int)f(3) };
+
+struct Bitfield {
+  unsigned int n : 1;
+  unsigned int m : fold((int)f(3));
+};
+
+void bitfield(struct Bitfield *b) {
+  b->n = (int)(6 * (1.0 / 3.0)); // norounding-warning {{changes value from 2 to 0}}
+}
+
+void vlas() {
+  // This is always a VLA due to its syntactic form.
+  typedef int vla1[(int)(-3 * (1.0 / 3.0))];
+  struct X1 { vla1 v; }; // expected-error {{fields must have a constant size}}
+
+  // This is always folded to a constant.
+  typedef int vla2[fold((int)(-3 * (1.0 / 3.0)))]; // expected-error {{negative size}}
+  struct X2 { vla2 v; };
+}