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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
>with -fnew-ra.
>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.

That sucks?

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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