Merge pull request #198 from dsharlet-intel/master

Adding math function support to the OpenCL C backend
Improve bounds calculation for divide-by-constant

Apply similar optimizations to those already found in
multiply-by-constant.
Merge pull request #200 from steven-johnson/master

Improve bounds calculation for divide-by-constant
Cleanup cpuid function.
Merge pull request #201 from florian-kriener/cpuid_cleanup

Cleanup cpuid function.
A restricted version of fast division logic for runtime divisors.

Turns out the most complex method works for all divisors (except for 1).

Seems to be a win when there's a multiply-keep-high-half
instruction available. We could make this the default implementation
of division, but it's restricted to small divisors and is slower for
32-bit numerators on my machine. Run test/performance/const_division.cpp
for performance numbers on your machine.
Merge branch 'master' of github.com:halide/Halide
Fixed address space metadata per current SPIR spec
Merge branch 'master' of https://github.com/halide/Halide