Mingw FPU init not Windows compatible.
Mingw initializes the FPU top 80 bit precision instead of MSVC's 53 bits (which is the standard). I suggest ghc linking on Windows should be changed to that it uses 53 bits instead. This will make programs more Windows compatible (and possibly faster).
Here's a comment from Mingw's Float.h:
/* MSVCRT.dll _fpreset initializes the control register to 0x27f, the status register to zero and the tag word to 0FFFFh. This differs from asm instruction finit/fninit which set control word to 0x37f (64 bit mantissa precison rather than 53 bit). By default, the mingw version of _fpreset sets fp control as per fninit. To use the MSVCRT.dll _fpreset, include CRT_fp8.o when building your application. */