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Re: What to do with new-ra for GCC 4.0
- From: neroden at fastmail dot fm (Nathanael Nerode)
- To: gcc at gcc dot gnu dot org
- Cc: stevenb at suse dot de
- Date: Sun, 2 Jan 2005 15:50:58 -0500
- Subject: Re: What to do with new-ra for GCC 4.0
Steven Bosscher wrote:
>Perhaps not so surprisingly, new-ra is completely broken on mainline
>at the moment. Literally not a single non-empty file will compile
>First of all there is a bug in ra-build.c:live_in() which has been
>there since the merge from the edge-vector-branch. Then we hit an
>ICE on sibcalls in ra.c:reg_alloc(), which also must have been there
>since ages. The patch below sort-of fixes these two issues. But
>then we hit SUBREG problems, probably due to rth's stricter subreg
>patches. At that point I gave up.
>So, any nontrivial code will ICE with -fnew-ra. I hate to bring up
>painful issues, but I would like to propose we remove all of new-ra
>for GCC 4.0 as it is complete and utterly broken anyway, and given
>that it has been broken for months without anyone complaining, it's
>not like anyone will miss it.
The structure of the new-ra files is really reasonably elegant; it would
be sad if it couldn't be salvaged.
Are there major structural defects in it, which would be remediated best by
writing a graph-coloring register allocator from scratch, or is it just
suffering from bitrot?
How many people understand the code? :-) Would more workers help?
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