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PRE (sometimes) confuses ivopts/scev?
- From: Richard Guenther <rguenth at tat dot physik dot uni-tuebingen dot de>
- To: gcc at gcc dot gnu dot org
- Date: Mon, 24 Jan 2005 14:03:36 +0100 (CET)
- Subject: PRE (sometimes) confuses ivopts/scev?
Hi!
Are there known bad interaction PRs wrt PRE and loop optimizations?
I found only PR18848 for PRE problems. Sometimes a lot better code
is created with -fno-tree-pre -- SCEV seems to be confused
and produces (for only extra IVs?) scev_not_known with PRE, but not
without, i.e. some uses are not detected?
Does this sound familiar to anyone?
Richard.
--
Richard Guenther <richard dot guenther at uni-tuebingen dot de>
WWW: http://www.tat.physik.uni-tuebingen.de/~rguenth/