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Groups > comp.lang.forth > #25646
| From | "Alex McDonald" <blog@rivadpm.com> |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: RAFTS beyond basic blocks; handling phi |
| Date | 2013-09-12 23:53 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <l0tgkl$7k2$1@dont-email.me> (permalink) |
| References | <l0neru$oj5$1@dont-email.me> <2013Sep11.125505@mips.complang.tuwien.ac.at> <l0pmjc$8ot$1@dont-email.me> |
on 11/09/2013 13:10:16, "Alex McDonald" wrote: > on 11/09/2013 11:55:06, Anton wrote: >> >> If there are loop back-edges involved, always choose to put the action >> on the back edge. > > OK. I presume there's a good reason for this; reduction in traffic? > Yes, from what I can see; but that brings me to a problem with generating back edges. Consider : foo begin + again ; If we don't insert a phi on the back edge, but simply balance the stack; B[1] <1> pop ( a ) B[1] <2> pop ( a|c b ) B[1] <3> + <1> <2> ( c ) B[1] push <3> ( -- ) B[1] jmp <1> OK, but inefficent. Better is B[1] <1> pop ( a ) B[1] <2> pop ( a|c b ) B[1] <4> + <2> <3> ( c ) B[1] <3> phi <1> <4> ( a|c ) B[1] jmp <2> A few issues. Now I have a DCG rather than a DAG. That can be resolved by marking visits while walking what is now a DCG. The other issue is determining that we need a B[1] jmp <2>; that is, not to the head of the block. Either that or the block is split between <1> and <2>; but again, how do we determine that? Can we use the left operand of <3> phi <1> <4> (the <1>, what would be the block entry) to select the split or branch point?
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RAFTS beyond basic blocks; handling phi "Alex McDonald" <blog@rivadpm.com> - 2013-09-10 16:46 +0100
Re: RAFTS beyond basic blocks; handling phi awegel@arcor.de (Alex Wegel) - 2013-09-10 23:30 +0200
Re: RAFTS beyond basic blocks; handling phi "Alex McDonald" <blog@rivadpm.com> - 2013-09-11 11:35 +0100
Re: RAFTS beyond basic blocks; handling phi Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-09-11 05:50 -0500
Re: RAFTS beyond basic blocks; handling phi "Alex McDonald" <blog@rivadpm.com> - 2013-09-11 12:07 +0100
Re: RAFTS beyond basic blocks; handling phi "Alex McDonald" <blog@rivadpm.com> - 2013-09-11 12:50 +0100
Re: RAFTS beyond basic blocks; handling phi anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-09-11 14:27 +0000
Re: RAFTS beyond basic blocks; handling phi anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-09-11 10:55 +0000
Re: RAFTS beyond basic blocks; handling phi "Alex McDonald" <blog@rivadpm.com> - 2013-09-11 13:10 +0100
Re: RAFTS beyond basic blocks; handling phi Bernd Paysan <bernd.paysan@gmx.de> - 2013-09-11 20:33 +0200
Re: RAFTS beyond basic blocks; handling phi "Alex McDonald" <blog@rivadpm.com> - 2013-09-11 19:53 +0100
Re: RAFTS beyond basic blocks; handling phi Bernd Paysan <bernd.paysan@gmx.de> - 2013-09-11 21:57 +0200
Re: RAFTS beyond basic blocks; handling phi anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-09-13 13:14 +0000
Re: RAFTS beyond basic blocks; handling phi albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-09-12 10:39 +0000
Re: RAFTS beyond basic blocks; handling phi "Alex McDonald" <blog@rivadpm.com> - 2013-09-12 23:53 +0100
Re: RAFTS beyond basic blocks; handling phi "Alex McDonald" <blog@rivadpm.com> - 2013-09-12 23:55 +0100
Re: RAFTS beyond basic blocks; handling phi "Alex McDonald" <blog@rivadpm.com> - 2013-09-13 10:16 +0100
Re: RAFTS beyond basic blocks; handling phi anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-09-13 13:19 +0000
Re: RAFTS beyond basic blocks; handling phi "Alex McDonald" <blog@rivadpm.com> - 2013-09-15 20:34 +0100
Re: RAFTS beyond basic blocks; handling phi anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-09-13 11:38 +0000
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