Re: Implement -Wswitch-fallthrough: libstdc++

[Marek Polacek]

2016-07-11  Marek Polacek  <pola...@redhat.com>

        PR c/7652
        * libsupc++/hash_bytes.cc: Use __builtin_fallthrough.

diff --git gcc/libstdc++-v3/libsupc++/hash_bytes.cc 
gcc/libstdc++-v3/libsupc++/hash_bytes.cc
index 2e5bbfa..818331f 100644
--- gcc/libstdc++-v3/libsupc++/hash_bytes.cc
+++ gcc/libstdc++-v3/libsupc++/hash_bytes.cc
@@ -95,8 +95,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       {
       case 3:
        hash ^= static_cast<unsigned char>(buf[2]) << 16;
+       __builtin_fallthrough ();
       case 2:
        hash ^= static_cast<unsigned char>(buf[1]) << 8;
+       __builtin_fallthrough ();
       case 1:
        hash ^= static_cast<unsigned char>(buf[0]);
        hash *= m;