NCG x86: implement wordToFloat directly in asm
Currently the x86 NCG calls into C to convert a word into a float. We should use CVTSI2SS/CVTSI2SD instructions instead (SSE/SSE2).
Code to fix in GHC.CmmToAsm.X86.CodeGen:
genWordToFloat :: BlockId -> Width -> CmmFormal -> CmmActual -> NatM InstrBlock
genWordToFloat bid width dst src =
-- TODO: generate assembly instead
genPrimCCall bid (word2FloatLabel width) [dst] [src]