[new-ra] "#if DENIS"

[Michael Matz]

Hi Denis,

On 4 Jul 2003, Denis Chertykov wrote:

> My code will transform
> ;; Begin of basic block 0
>   3	p59 <= [h16]:SI
>
> to
>   3	p86' <= [h16]:SI
>
> But, your to
> ;; Begin of basic block 0
>   3	p59 <= [h16]:SI
>   203`	p86' <= p59

Yes.  I think that is because our different view on pseudo webs.  I think
of them as being stack slots already, and hence I can't do the
transformation you do, because that would mean the insn has two memory
references (the load from [h16] and the store to p86').  This
transformation _is_ tried in my code, but rejected because an invalid
instruction would result in case the pseudo web can not be colored later,
which would mean a reload.  But that's the same in your version.  In the
insn "3   p86' <= [h16]:SI" you also could have two memory accesses, if
p86 is not colored.

With your patch the code for the fetch.c example is clearly better, but
I'm not sure about more complex examples which could require reloads.  How
do you think this is handled?


Ciao,
Michael.