Fix TableGen subtarget-emitter to handle A9/Swift.

A9 uses itinerary classes, Swift uses RW lists. This tripped some
verification when we're expanding variants. I had to refine the
verification a bit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178357 91177308-0d34-0410-b5e6-96231b3b80d8
[mips] Define a function which returns the GPR register class.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178359 91177308-0d34-0410-b5e6-96231b3b80d8
Implement FRINT lowering on PPC using frin

Like nearbyint, rint can be implemented on PPC using the frin instruction. The
complication comes from the fact that rint needs to set the FE_INEXACT flag
when the result does not equal the input value (and frin does not do that). As
a result, we use a custom inserter which, after the rounding, compares the
rounded value with the original, and if they differ, explicitly sets the XX bit
in the FPSCR register (which corresponds to FE_INEXACT).

Once LLVM has better modeling of the floating-point environment we should be
able to (often) eliminate this extra complexity.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178362 91177308-0d34-0410-b5e6-96231b3b80d8