Implement -Wimplicit-fallthrough.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@240485 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 57 insertions, 0 deletions

diff --git a/gcc/testsuite/c-c++-common/attr-fallthrough-1.c b/gcc/testsuite/c-c++-common/attr-fallthrough-1.c
new file mode 100644
index 00000000000..ecfd094d9cd
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/attr-fallthrough-1.c
@@ -0,0 +1,57 @@
+/* PR c/7652 */
+/* { dg-do compile } */
+/* { dg-options "-Wall -Wextra -Wpedantic" } */
+
+extern void bar (int);
+void
+fn (int i)
+{
+  __attribute__((fallthrough)) int j = 0; /* { dg-warning "ignored|attribute not followed" } */
+
+  if (j)
+    __attribute__((fallthrough));  /* { dg-error "invalid use" } */
+
+  __attribute__((fallthrough));  /* { dg-error "invalid use" } */
+  switch (i)
+  {
+    __attribute__((fallthrough)); /* { dg-warning "statement will never" } */
+  case 1:
+   i++;
+   __attribute__((fallthrough));
+  case 2:
+    if (i) /* { dg-warning "statement may fall through" } */
+      bar (2);
+    else
+      __attribute__((fallthrough));
+  case 3:
+    if (i > 1)
+      __attribute__((fallthrough));
+    else
+      return;
+  case 4:
+    if (i)
+      __attribute__((fallthrough)); /* { dg-warning "not preceding" } */
+    __attribute__((fallthrough));
+  case 5:
+   ;
+   __attribute__((fallthrough));
+  case 6:
+    if (i) /* { dg-warning "statement may fall through" } */
+      bar (6);
+    else
+      {
+	__attribute__((fallthrough));
+      }
+  case 7:
+    if (i > 1)
+      {
+	__attribute__((fallthrough));
+      }
+    else
+      bar (7); /* { dg-warning "statement may fall through" } */
+  default:
+    --j;
+  }
+
+  __attribute__((fallthrough)); /* { dg-error "invalid use" } */
+}