This commit introduces a set of experimental intrinsics intended to prevent
optimizations that make assumptions about the rounding mode and floating point
exception behavior. These intrinsics will later be extended to specify
flush-to-zero behavior. More work is also required to model instruction
dependencies in machine code and to generate these instructions from clang
(when required by pragmas and/or command line options that are not currently
supported).
Differential Revision: https://reviews.llvm.org/D27028
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293226 91177308-0d34-0410-b5e6-96231b3b80d8
