Replacement for GMP: Update

[Peter Tanski]

Simon,

> Possibly, yes.  IIRC, -O3 was mainly to get some loop unrolling.  This
> is a performance-critical part of the system though, and when  
> making any
> changes we like to measure things to make sure we haven't pessimised
> performance.

I will try to test it both ways, then.  Also, -optc-O3 is turned on  
even for debug builds since GC_HC_OPTS is set unconditionally.  I  
could change it to:

	ifneq (,$(findstring $(SRC_HC_OPTS), -DDEBUG))
	GC_HC_OPTS += -optc-O3
	endif


>> (3) I have been looking at how to implement a dual-constructor-in-a-
>> pointer for Integer (i.e., merge constructors of small Integers and
>> big Integers into the Int#).  Would that solution be workable or
>> might it break current Haskell programs?  Just a thought.
>
> Which representation in particular are you talking about here?

I was talking about the definition of Integer in packages/base/GHC/ 
Num.lhs particularly the implementation in PrimOps.cmm, which returns  
Integers as:

    /* returns (# size  :: Int#,
		         data  :: ByteArray# #)
    */
    RET_NP(s,p);

If the ByteArray were indicated through a pointer, the representation  
in Haskell would be

	J# IntegerT#
	{- new type, depending on pointer size,
	   either holding 30 or 62 bits of precision -}

and a Cmm procedure returning an Integer would be:

	RET_NP(p);

I hope this doesn't confuse you.

Best regards,
Peter