RFC: Disable RTL inlininer for Java?

Steven Bosscher s.bosscher@student.tudelft.nl
Thu May 30 04:40:00 GMT 2002


Op do 30-05-2002, om 12:50 schreef David S. Miller:
>    From: Steven Bosscher <s.bosscher@student.tudelft.nl>
>    Date: 30 May 2002 12:59:48 +0200
>    
>    It would be a huge job to have GNAT and g77 use the tree inliner
>    because they don't build functions as trees.
>    
>    Also, the tree inliner still depends on stuff from c-*.
> 
> Moving to trees is something the GNAT and g77 folks are going to need
> to consider for reasons far from the scope of inlining.

Your right about that of course. I just wanted to point out that it
could be a heckuva job to *rewrite* these front ends to build functions
at trees. Who's going to do that?

Killing the RTL inliner now seems premature to me at least. I think it's
a good idea for the long term. You could make the RTL inliner deprecated
for, say, 3.3, and kill it for 3.4 and beyond, but for now I think it
should stay. And in a working state, of course.

Actually it may not be that hard to make GNAT build functions as trees,
I don't know GNAT too well. But have you ever looked at g77? And GNU
Pascal doesn't build functions as trees, either. These front ends need
time to adapt. 

Besides, what infrastructure would you suggest these front ends use?
*Everything* at a higher level than RTL is still quite C-family specific
on the mainline. Maybe it's better to wait for the simplified tree
representation (as used on the ast-optimizer branch) to mature, and work
on other infrastructure changes that allow these front ends to use the
tree optimizations (including the tree inliner).

Greetz
Steven




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