New register allocator branch created

[Daniel Berlin]

On Sun, 28 Jan 2001, Richard Kenner wrote:

>     For instance, for cp-demangle.c, the older allocator does this on
>     demangle_special name:
>
> This had 54 spills.
>
>     The new one does this:
> \
> It has 90 spills.
>
> So I'm not sure what you are showing.

err, your numbers are wrong.
Those 90 spills aren't real spills, they are scratches/symbol_refs being
filled in by reload.

Reloads for insn # 39
Reload 0: reload_out (SI) = (scratch:SI)
	LINK_REGS, RELOAD_FOR_OUTPUT (opnum = 4)
	reload_out_reg: (scratch:SI)
	reload_reg_rtx: (reg:SI 65 lr)

Like that.

The 54 spills are real spills.

If reload finds a reg, it hasn't really spilled.
So when it says "Spilling reg 65", it really spilled.


>
>     Would it make you feel better if i just said it performs " a ton" better
>     or some other vague, not applicable at all term?
>
> It would actually be good if you could quantify the performance improvement.
> You could compare the static number of memory spills/fills, the number or
> register-register copies, or performance of test cases, perhaps even SPEC.

Don't have time right now.
But when i do, I will.
--Dan