Re: [PATCH] Implementing Swing Modulo Scheduling in GCC

[Mark Mitchell <mark at codesourcery dot com>]

Mostafa Hagog wrote:

> We addressed the comments below.  The troubled code (unrolling and
> renaming) was removed and replaced by a direct dependence computation
> using df.c.  We also added support for loops with unknown bounds.
>
> Here is the revised patch relative to mainline.   Passed regression
> and bootstrap on powerpc-apple-darwin7.2.0 target.
I'm not going to approve the patch as it stands. 

However, I think it looks very good; it's certainly tidy and has better 
documentation than many patches.  Furthermore, the algorithm looks like 
a good choice.

Before check-in the patch should be tested on three architectures.  I'd 
suggest IA32 GNU/Linux and IA64 GNU/Linux in addition to OS X.  Also, 
are you able to post SPEC 2000 numbers with and without the patch on 
these platforms?  That would help to demonstrate that the patch is doing 
useful stuff on code that a lot of people believe should benefit from 
these kinds of improvements.  Finally, you should post compile-time 
performance with and without the patch.  It's reasonable for the 
compile-time performance to get a little worse if the SPEC nubmers are 
getting better, but the impact should hopefully be minimal.

Thanks,

--
Mark Mitchell
CodeSourcery, LLC
(916) 791-8304
mark@codesourcery.com