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Re: [tree-ssa] New regressions as of 2003-11-04
- From: law at redhat dot com
- To: Richard Henderson <rth at redhat dot com>
- Cc: Andrew MacLeod <amacleod at redhat dot com>, Diego Novillo <dnovillo at redhat dot com>, Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>, Daniel Berlin <dberlin at dberlin dot org>, Jan Hubicka <jh at suse dot cz>, gcc mailing list <gcc at gcc dot gnu dot org>
- Date: Tue, 04 Nov 2003 17:08:09 -0700
- Subject: Re: [tree-ssa] New regressions as of 2003-11-04
- Reply-to: law at redhat dot com
In message <20031104230929.GA24820@redhat.com>, Richard Henderson writes:
>On Tue, Nov 04, 2003 at 03:08:53PM -0700, law@redhat.com wrote:
>> Right, but the remove_useless_stmts_and_vars does kill the CFG.
>
>No it doesn't. Mostly because at present it doesn't do
>anything at all when called after lowering. And, really,
>I don't see how it could.
I must admit I haven't looked closely at it since all the lowering, so
you may in fact be correct.
>If you want to clean up out-of-ssa bits, I suggest running
>another dominator pass, geared to detect this sort of thing.
Another dom pass isn't going to improve this kind of code. Either the
useless statement remover needs to be updated, or we need something to
eliminate the PHI, or the out-of-ssa pass needs to get a lot smarter.
jeff