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Re: Bugs in SSA-CCP and SSA-PRE optimizers

From: Daniel Berlin <dberlin at dberlin dot org>
To: Diego Novillo <dnovillo at redhat dot com>
Cc: Steven Bosscher <s dot bosscher at student dot tudelft dot nl>, gcc at gcc dot gnu dot org
Date: Tue, 17 Sep 2002 17:04:57 -0400
Subject: Re: Bugs in SSA-CCP and SSA-PRE optimizers

The useless assignment to T.1 will not be detected by PRE.  You
need copy propagation for that.

Also, why is "foo = pretmp.2 = 1 * 2" not folded?

PRE should be folding expressions.  It should also be calling the
simplifier again, from what I can see.

I'll have it fold the expressions in a moment (I'm about to submit strength reduction).
It will also generate only simple statements now.

Diego.

References:
- Re: Bugs in SSA-CCP and SSA-PRE optimizers
  - From: Diego Novillo

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