This PR reports a bogus -Wimplicit-fallthrough warning on the attached test.
The problem is that last_stmt_in_scope should for GIMPLE_TRY, if the last
statement of the eval part can't fallthrough, return this statement and don't
warn. And the same should be true for FALLTHROUGH (). This patch fixes it.
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2016-09-30 Marek Polacek <pola...@redhat.com>
PR c++/77803
* gimplify.c (last_stmt_in_scope): Add check for FALLTHROUGH ().
* g++.dg/warn/Wimplicit-fallthrough-1.C: New test.
diff --git gcc/gimplify.c gcc/gimplify.c
index 66bb8be..97d63db 100644
--- gcc/gimplify.c
+++ gcc/gimplify.c
@@ -1687,6 +1687,7 @@ last_stmt_in_scope (gimple *stmt)
stmt = gimple_seq_last_stmt (gimple_try_eval (try_stmt));
gimple *last_eval = last_stmt_in_scope (stmt);
if (gimple_stmt_may_fallthru (last_eval)
+ && !gimple_call_internal_p (last_eval, IFN_FALLTHROUGH)
&& gimple_try_kind (try_stmt) == GIMPLE_TRY_FINALLY)
{
stmt = gimple_seq_last_stmt (gimple_try_cleanup (try_stmt));
diff --git gcc/testsuite/g++.dg/warn/Wimplicit-fallthrough-1.C
gcc/testsuite/g++.dg/warn/Wimplicit-fallthrough-1.C
index e69de29..8f80b01 100644
--- gcc/testsuite/g++.dg/warn/Wimplicit-fallthrough-1.C
+++ gcc/testsuite/g++.dg/warn/Wimplicit-fallthrough-1.C
@@ -0,0 +1,16 @@
+// PR c++/77803
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wimplicit-fallthrough" }
+
+struct A {};
+int a;
+void fn1() {
+ switch (0) {
+ case 0: {
+ A b;
+ [[fallthrough]];
+ }
+ default:
+ a = 0;
+ }
+}
Marek
