[PowerPC] Add variants of "sync" instruction

This adds support for the "sync $L" instruction with operand,
and provides aliases for "lwsync" and "ptesync".



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185344 91177308-0d34-0410-b5e6-96231b3b80d8

[PowerPC] Add some existing instructions to ppc64-encoding-bookII.s

The test case had a couple of FIXMEs where the instruction is in
fact already supported by the back-end.  In some other case, while
the generic form of the instruction is not yet supported, a
specialized form is.  This adds tests for those already supported
instructions / instruction forms.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185347 91177308-0d34-0410-b5e6-96231b3b80d8
Added c++ mode selector to head of SelectionDAGBuilder.h so editors open it in c++ mode instead of c mode.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185348 91177308-0d34-0410-b5e6-96231b3b80d8