Add a paragraph about MCTargetStreamer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192265 91177308-0d34-0410-b5e6-96231b3b80d8
Add in64BitMode/in32BitMode to the MMX/SSE2/AVX maskmovq/dq instructions. This way the asm parser will pick the right one based on the mode. Instruction selection already did the right thing based on the pointer size.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192266 91177308-0d34-0410-b5e6-96231b3b80d8