X86: When expanding PCMPGTQ to PCMPGTD we always want to compare the lower halves as unsigned.

Take #2 on fixing PR15977.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182486 91177308-0d34-0410-b5e6-96231b3b80d8
[Support] Add StringMap::swap() and a default ctor for iterators

This makes StringMap<> more compatible with std::map<std::string, ...>.

Differential Revision: http://llvm-reviews.chandlerc.com/D842

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182487 91177308-0d34-0410-b5e6-96231b3b80d8
Add the IncludeSelf parameter to the MCSubRegIterator and MCSuperRegIterator
constructors.  No functional change.
Part of rdar://12906217


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182490 91177308-0d34-0410-b5e6-96231b3b80d8
Fix StringMapIterator compile errors for non-MSVC compilers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182493 91177308-0d34-0410-b5e6-96231b3b80d8