Add Hardware Transactional Memory (HTM) Support
This patch adds Hardware Transaction Memory (HTM) support supported by ISA 2.07
(POWER8). The intrinsic support is based on GCC one , with both 'PowerPC HTM
Low Level Built-in Functions' and 'PowerPC HTM High Level Inline Functions'
Along with builtins a new driver switch is added to enable/disable HTM
instruction support (-mhtm) and a header with common definitions (mostly to
parse the TFHAR register value). The HTM switch also sets a preprocessor builtin
The HTM usage requires a recently newer kernel with PPC HTM enabled. Tested on
powerpc64 and powerpc64le.
This is send along a llvm patch to enabled the builtins and option switch.
Phabricator Review: http://reviews.llvm.org/D8248