Add FP_CONTRACT support for clang.

Clang will now honor the FP_CONTRACT pragma and emit LLVM
fmuladd intrinsics for expressions of the form A * B + C (when they occur in a
single statement).



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164989 91177308-0d34-0410-b5e6-96231b3b80d8
21 files changed