On 02/01/2013 08:03 AM, Simon Marlow wrote:
On 31/01/13 20:30, Geoffrey Mainland wrote:
2) SSE support is processor and platform dependent. What is the proper way for the programmer to know what SSE primitives are available? A CPP define? If so, what should it be called?
Right now one can look at the TARGET_* and __GLASGOW_HASKELL_LLVM__ CPP macros and make a decision as to whether or not SSE primitives are available, but that's not a great solution. Also, what happens when we want to add AVX support? How do we control the inclusion of AVX support when building GHC, and how do we let the programmer know that the AVX primops/primtypes are available for use?
We #define __SSE__: http://hackage.haskell.org/trac/ghc/ticket/7554
Similar things would need to happen for AVX.
If I invoke ghc with -msse on a Win32 box then __SSE__ will be 1, but that doesn't mean I will be able to use SSE primops due to the stack alignment issue on that platform. Also, the decision as to whether or not SSE primops will be available at all needs to be made when GHC is itself built. How should we expose that knob? As an aside, what's the proper way for me to test the ARM cross-compilation support? I'm afraid my patches may break things there. Thanks, Geoff