gnupic: SDCC register optimization
Subject:
Re: SDCC register optimization
From:
Scott Dattalo ####@####.####
Date:
4 Jul 2002 20:02:55 -0000
Message-Id: <Pine.LNX.4.44.0207041246260.24403-100000@ruckus.brouhaha.com>
On Tue, 2 Jul 2002, Scott Dattalo wrote:
>
> A new register optimization algorithm has been added to SDCC. This should
> tremendously help applications that use pointers. For example, the
> regression program pointer1.c:
>
> http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/sdcc/sdcc/src/regression/pointer1.c
>
> when compiled with the latest version of SDCC saves 25 registers:
>
> $ sdcc -S -mpic14 pointer1.c
> *** Saved 11 registers ***
> *** Saved 12 registers, total saved 23 ***
> *** Saved 2 registers, total saved 25 ***
>
> That's 25 out of the 40 originally declared! There's still room for
> improvement, but this is a fairly significant enhancement that a few of
> you can benefit from.
And today, it's up to:
*** Saved 12 registers ***
*** Saved 21 registers, total saved 33 ***
Again, that's 33 out of 40 registers have been optimized out! It's getting
hard to simulate the test code because the optimizer is eroding it away.
Scott
