[PATCH] Fix some 28_regex/ fallout

[Marek Polacek]

This fixes some testsuite fallout in 28_regex/.  The problem was that
with -m32 we were triggering UB in a shift.  Fixed by multiplying the
RHS of the shift-expression by 0 if we are not going to use the cache.

Regtested/bootstrapped on ppc64-linux, ok for trunk?

2014-12-03  Marek Polacek  <pola...@redhat.com>

        * include/bits/regex_compiler.h (_S_cache_size): Multiply the
        RHS of the shift-expression by _UseCache::value.

diff --git gcc/include/bits/regex_compiler.h gcc/include/bits/regex_compiler.h
index d8880cc..2b2b8e0 100644
--- gcc/include/bits/regex_compiler.h
+++ gcc/include/bits/regex_compiler.h
@@ -417,7 +417,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       typedef typename std::is_same<_CharT, char>::type _UseCache;
 
       static constexpr size_t
-      _S_cache_size() { return 1ul << (sizeof(_CharT) * __CHAR_BIT__); }
+      _S_cache_size() { return 1ul << (sizeof(_CharT) * __CHAR_BIT__
+                                      * int(_UseCache::value)); }
 
       struct _Dummy { };
       typedef typename std::conditional<_UseCache::value,

        Marek