Fix array constant expression evaluation bug: we can have different values for
different array elements, even if they're all constructed using the same
default constructor.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@180017 91177308-0d34-0410-b5e6-96231b3b80d8
cmake: Only add -pedantic if LLVM didn't add it. Don't unconditionally add
-Wall -W, since it's already provided by LLVM's cmake config, and that
overrides fixes (such as -Wno-uninitialized) which LLVM's cmake setup may have
provided.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@180018 91177308-0d34-0410-b5e6-96231b3b80d8
C++1y constexpr extensions, round 1: Allow most forms of declaration and
statement in constexpr functions. Everything which doesn't require variable
mutation is also allowed as an extension in C++11. 'void' becomes a literal
type to support constexpr functions which return 'void'.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@180022 91177308-0d34-0410-b5e6-96231b3b80d8