------- Additional Comments From law at redhat dot com 2005-06-02 05:22 -------
Subject: Re: [4.1 regression] ICE:
-ftree-vectorize, segfault
On Wed, 2005-06-01 at 13:22 +0000, dorit at il dot ibm dot com wrote:
> The best thing would be to detect such redundant phis and clean them up, and
> in
> the vectorizer work under the assumption that they don't exit. The code to do
> peeling would be cleaner (not having to consider these special cases), and we
> would generate much less code (see below how many phis we end up generating
> when peeling before and after this loop).
I'd tend to agree that it would be better if these dead PHIs were
cleaned up before the loop optimizer is run -- however, I would
strongly recommend that the loop optimizer handle this case.
The basic idea being that feeding an optimizer, any optimizer
with sub-optimal code (ie, dead phis, unpropagated constants
and copies, etc etc) should not cause an optimizer to segfault,
abort or generate incorrect code.
Jeff
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21734
