Re: [PATCH] Removing two-arg ne

[Dan Sugalski]

At 9:02 PM +0100 10/11/02, Nicholas Clark wrote:

On Fri, Oct 11, 2002 at 01:30:33PM -0400, Dan Sugalski wrote:

 At 7:10 PM +0200 10/10/02, Leopold Toetsch wrote:
 >
 >There are also 2 operand math operations of dubious achievement:

 >Each of them will be doubled for each RHS INT argument giving ~25 opcodes.

 Those are all for the:

    a op= b

 form. There's a minor benefit to keeping them.

I would like to kill all generated variants of all the 3 argument opcodes
where both input arguments are constants. They truly are superfluous.

Where both operands are ints or nums, I think it's a good idea. I'm less sure in the case where there's a PMC or string involved, as there may be some assumption of runtime behaviour (in the case of constant PMCs that might have some methods overloaded) or strings where the compiler is expecting runtime conversion to happen before whatever gets done.

 > >I would kill these too.

 >IMHO a smaller core will perform better, then the above saving of 1
 >operand in the byte code can achieve.

 Maybe, but I'm unconvinced. We are going to do a cull of the opcodes
 before release, but I'm not inclined to do it now, and I'm not really
 sure that there'll be any speed win at all from it. Size win, yes,
 but still, not much. (And we do want the two-arg forms that use PMCs,

It should make the computed goto core compile more rapidly.

True, though I'm not hugely worried about this, as it happens only once.

It might also make the computed goto core run more efficiently, as by
being smaller it will bring more frequently used opcodes closer together.
(Although we can probably have a larger effect by specificy a sort order
either by iterative benchmarking the speed of parrot with different orders,
or by code coverage profiling to find the most common opcodes.)
Not much gain, but it might be worth it if we can automate the discovery
process.

True. I think reordering is a bigger win, honestly. Lightly used opcode functions won't get swapped in until they're really needed.

--
Dan

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