From: Michael Hayes <m.hayes@elec.canterbury.ac.nz>
To: egcs@cygnus.com
Cc: Michael Hayes <m.hayes@elec.canterbury.ac.nz>
Subject: Re-run of loop pass
Date: Sat, 17 Oct 1998 19:32:00 -0000 [thread overview]
Message-ID: <13865.9178.455954.70561@ongaonga.elec.canterbury.ac.nz> (raw)
What's the philosophy of rerunning the loop optimisation pass twice?
I've noticed that this can generate poorer code when unrolling loops
or using the bct optimisation if a BIV is eliminated on the first
pass.
On the second pass, loop_iterations is often unable to determine the
iteration count for loops with limits that should be able to be
determined at compile time. Loop unrolling or the bct optimisation
then makes a dog's breakfast of things.
Michael.
next reply other threads:[~1998-10-17 19:32 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
1998-10-17 19:32 Michael Hayes [this message]
1998-10-18 0:15 ` Jeffrey A Law
1998-10-18 3:11 ` Michael Hayes
1998-10-18 11:04 ` David Edelsohn
1998-10-18 12:43 ` Mark Mitchell
1998-10-18 18:52 ` Michael Hayes
1998-10-21 23:18 ` Richard Henderson
1998-10-22 9:28 ` Jeffrey A Law
1998-10-22 21:15 ` Toon Moene
1998-10-23 2:57 ` Michael Hayes
1998-10-23 2:57 ` Michael Hayes
1998-10-23 2:57 ` Jeffrey A Law
1998-10-23 2:57 ` Michael Hayes
1998-10-25 13:53 ` Problem compiling python Hasan Diwan
1998-10-30 2:40 ` Alexandre Oliva
1998-11-04 20:47 ` Re-run of loop pass Joern Rennecke
1998-11-05 0:28 ` Michael Hayes
1998-11-04 20:47 ` Joern Rennecke
1998-11-05 5:01 ` Michael Hayes
1998-10-23 17:45 ` Toon Moene
1998-10-23 17:45 ` Michael Hayes
1998-10-18 6:11 ` Toon Moene
1998-10-18 17:19 ` Michael Hayes
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