[Bug tree-optimization/19038] [4.0 Regression] out-of ssa causing loops to have more than one BB

["law at redhat dot com" <gcc-bugzilla@gcc.gnu.org>]

------- Additional Comments From law at redhat dot com  2005-01-04 04:04 -------
Subject: Re:  [4.0 Regression] out-of ssa
	causing loops to have more than one BB

On Thu, 2004-12-30 at 21:51 +0000, pinskia at gcc dot gnu dot org wrote:
> ------- Additional Comments From pinskia at gcc dot gnu dot org  2004-12-30 21:50 -------
> (In reply to comment #34)
> Actually it is because we are placing statements in the loop's latch.
> It is done in create_new_iv.
So just to be clear, it's not my change that is causing a regression.
The IV code creates situations which prevent my change from having
any kind of impact because the loop backedge is already split by
the IV code (and thus the loop backedge is no longer critical and
my out-of-ssa code does nothing).

Right?

Jeff

ps.  It seems to me that the IV code could use a trick similar to what I
did to the out-of-ssa code.  The only significant complication would be
that the IV code would have to verify that the code it wants to insert
is safe on both path (loop backedge and loop exit).





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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19038