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Re: Synthetic register related: consequences of changing Frame layout.
- From: Andy Walker <ja_walker at earthlink dot net>
- To: dewar at gnat dot com (Robert Dewar),denisc at overta dot ru
- Cc: gcc at gcc dot gnu dot org
- Date: Sun, 5 Jan 2003 22:54:40 -0600
- Subject: Re: Synthetic register related: consequences of changing Frame layout.
- References: <20030105114048.DAAFDF2E18@nile.gnat.com>
On Sunday 05 January 2003 05:40 am, Robert Dewar wrote:
<snip>
> Have you even looked at how code is currently
> generated.
Yes.
> Registers are spilled to the local stack frame, and of course
> you get the normal 3-byte instructions to transfer to and from the spill
> locations.
With Synthetic registers, you also get a nice set of instructions to handle
data directly in the Synthetic registers without needing any transfer to a
natural register -- add, add immediate, xor, neg, rotr, to name a few.
Another big plus is that Synthetic registers are directly used in
instructions, instead of requiring a move from a spill location to a natural
register before being used.
> There is too much general "I believe" guesswork in your approach
> and not enough hard knowledge.
I can only agree.
>From experience, I hope to gain wisdom.
Andy