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Groups > comp.lang.forth > #56695

Re: LLVM and Forth

From Spiros Bousbouras <spibou@gmail.com>
Newsgroups comp.lang.forth
Subject Re: LLVM and Forth
References (2 earlier) <ac4976d7-955a-45e3-9cdd-e339e15acbc2@googlegroups.com> <ZqGdnRes4qCBI33FnZ2dnUU7-VednZ2d@supernews.com> <065e774c-c5fb-4e68-9489-00b5357142d6@googlegroups.com> <qOKdneQNfs-vmH_FnZ2dnUU7-UednZ2d@supernews.com> <72a319fa-8035-4a17-a5a2-2b2884a57b15@googlegroups.com>
Message-ID <znLEA.278723$Fa7.82064@fx09.am4> (permalink)
Organization virginmedia.com
Date 2017-04-04 11:24 +0000

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On Tue, 4 Apr 2017 03:25:27 -0700 (PDT)
krishna.myneni@ccreweb.org wrote:
> On Monday, April 3, 2017 at 3:17:59 AM UTC-5, Andrew Haley wrote:
> > Single-threaded, it wouldn't be problematic at all.  The nasal daemons
> > tend to happen if you're pushing the envelope of optimization.  As
> > long as you translated into well-defined C, ...
> 
> Let's consider an example. Here is the Forth code:
> 
> variable v
> 0 v !
> 
> v @ 1+ 2 +  v !
> 
> Now this could be translated into C in a couple of ways:
> 
> T1)
> 
> int v = 0;
> v = ++v + 2;
>
> T2)
> 
> int v = 0;
> v = v++ + 2;
> 
> My understanding is that, per the C standard, translation T1 is well-defined,
> but translation T2 results in undefined code. I'm still trying to wrap my
> head around sequence points, but understanding why one translation is
> well-defined while the other is undefined seems to presents a challenge for
> writing a translator.

No , they are both undefined behaviour. A correct translation is in fact the
most straightforward one , namely

int v = 0;
v++ ;
v += 2 ;

As for wrapping one's head around sequence points you make it sound as if it's some
complicated topic. It's actually trivial. As I was expecting , there is a wikipedia
article , en.wikipedia.org/wiki/Sequence_point (not the most authoritative source
but with a quick look I don't see any obvious errors). A draft of the C standard can
be found online and it even helpfully collects all the sequence points in annex C.
And if you have doubts about anything in there or in the wikipedia article you can
always ask on  comp.lang.c .So if one has any confusion on sequence points it must
be because they didn't bother to ask or search in the most obvious places. Obviously
if one wants to write a Forth (or anything else) to C translator then they must know
enough C (and Forth !).

-- 
South Dakota today passed the most restrictive abortion law in the country.
It includes the requirement that pregnant wives notify both their husband
AND the baby's father.
  <S1797.1b42@netfunny.com>

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LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-01 06:36 -0700
  Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-01 14:57 +0000
    Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-01 11:55 -0700
      Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-02 15:24 +0000
  Re: LLVM and Forth rickman <gnuarm@gmail.com> - 2017-04-01 11:21 -0400
    Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-01 11:57 -0700
      Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-02 04:02 -0500
        Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-02 06:35 -0700
          Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-02 14:41 +0000
          Re: LLVM and Forth minforth@arcor.de - 2017-04-03 01:09 -0700
            Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-03 05:32 -0700
              Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-03 13:52 +0000
                Re: LLVM and Forth minforth@arcor.de - 2017-04-03 07:59 -0700
                Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-03 16:08 +0000
                Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-03 12:22 -0500
                Re: LLVM and Forth Paul Rubin <no.email@nospam.invalid> - 2017-04-03 20:10 -0700
                Re: LLVM and Forth minforth@arcor.de - 2017-04-03 22:19 -0700
                Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-04 16:12 +0200
                Re: LLVM and Forth Walter Banks <walter@bytecraft.com> - 2017-04-05 17:27 -0400
            Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-03 14:29 +0000
          Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-03 03:17 -0500
            Re: LLVM and Forth minforth@arcor.de - 2017-04-03 05:04 -0700
            Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-03 12:55 +0000
              Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-03 10:08 -0500
                Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-03 17:05 +0000
                Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-04 11:29 -0500
                Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-04 19:11 +0200
                Re: LLVM and Forth Paul Rubin <no.email@nospam.invalid> - 2017-04-04 21:29 -0700
                Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-05 15:01 +0000
                Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-05 18:42 +0100
                Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-06 04:01 -0500
                Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-06 18:48 +0000
                Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-06 18:42 -0700
                Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-07 04:02 -0500
                Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-08 21:18 -0700
                Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-08 22:43 +0000
                Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-08 20:54 -0700
                Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-09 14:53 +0000
                Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-10 00:38 +0000
                Re: LLVM and Forth James Kuyper <jameskuyper@verizon.net> - 2017-04-09 22:46 -0400
                Re: LLVM and Forth Robert Wessel <robertwessel2@yahoo.com> - 2017-04-09 22:27 -0500
                Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-10 12:36 +0000
                Re: LLVM and Forth Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-10 14:09 +0100
                Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-10 13:07 +0000
                Re: LLVM and Forth Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-10 16:18 +0100
                Re: LLVM and Forth "James R. Kuyper" <jameskuyper@verizon.net> - 2017-04-10 11:51 -0400
                Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-12 21:32 +0000
                Re: LLVM and Forth "James R. Kuyper" <jameskuyper@verizon.net> - 2017-04-12 18:29 -0400
                Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-12 15:29 -0700
                Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-13 02:55 +0200
                Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-10 18:38 -0700
                Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-10 11:54 -0500
                Re: LLVM and Forth Paul Rubin <no.email@nospam.invalid> - 2017-04-10 10:17 -0700
              Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-03 17:02 +0100
              Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-03 10:03 -0700
            Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-04 03:25 -0700
              Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-04 11:24 +0000
                Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-04 04:55 -0700
                Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-04 12:28 +0000
                Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-04 16:16 +0000
              Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-04 15:38 +0200
                Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-04 16:06 +0200
                Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-04 17:57 -0700
                Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-05 00:44 -0400
                Re: LLVM and Forth minforth@arcor.de - 2017-04-05 00:00 -0700
                Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-05 08:47 -0700
                Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-05 11:04 -0500
                Re: LLVM and Forth john <anon@example.com> - 2017-04-05 18:04 +0100
                Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-05 13:04 -0700
                Re: LLVM and Forth Paul Rubin <no.email@nospam.invalid> - 2017-04-05 18:20 -0700
                Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-05 20:14 -0700
                Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-06 12:33 +0000
                Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-06 10:49 -0700
                Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 18:55 +0100
                Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-06 20:41 +0000
                Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 21:47 +0100
                Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 21:56 +0100
                Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-06 23:59 -0400
                Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-06 17:10 -0700
                Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-07 03:33 -0400
                Re: LLVM and Forth Spiros Bousbouras <spibou@gmail.com> - 2017-04-08 22:48 +0000
                Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-09 15:06 -0400
                Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-08 22:45 -0700
                Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-09 14:27 +0000
                Re: LLVM and Forth Joel Rees <joel.rees@gmail.com> - 2017-04-09 21:26 -0700
                Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-09 13:35 -0400
                Re: LLVM and Forth Paul Rubin <no.email@nospam.invalid> - 2017-04-09 14:07 -0700
                Re: LLVM and Forth minforth@arcor.de - 2017-04-05 12:16 -0700
                Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-05 20:27 -0700
                Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-06 05:24 -0400
                Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-06 03:26 -0700
                Re: LLVM and Forth minforth@arcor.de - 2017-04-06 04:05 -0700
                Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-06 06:50 -0500
                Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-06 05:23 -0400
                Re: LLVM and Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-06 04:44 -0500
                Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 10:57 +0100
                Re: LLVM and Forth peter.m.falth@gmail.com - 2017-04-05 05:29 -0700
                Re: LLVM and Forth "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-04-14 02:04 +0000
                Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-15 14:03 +0200
                Re: LLVM and Forth "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-04-16 00:44 +0000
                Re: LLVM and Forth alex@rivadpm.com - 2017-04-16 05:53 -0700
                Re: LLVM and Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-16 15:43 +0000
                Re: LLVM and Forth "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-04-16 22:27 +0000
                Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-18 02:45 +0200
                Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-18 18:26 +0100
                Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-20 19:51 +0200
                Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-20 19:08 +0100
                Re: LLVM and Forth albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-20 20:42 +0200
                Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-20 20:29 +0100
                Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-20 20:48 +0100
                Re: LLVM and Forth "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-04-21 11:49 +0000
          Re: LLVM and Forth Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-04-03 20:39 -0400
  Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-02 21:15 +0100
    Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-02 15:18 -0700
      Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-03 13:07 +0100
        Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-03 09:45 -0700
          Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-03 22:52 +0100
            Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-03 15:25 -0700
              Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 09:35 +0100
      Re: LLVM and Forth antispam@math.uni.wroc.pl - 2017-04-06 01:36 +0000
        Re: LLVM and Forth minforth@arcor.de - 2017-04-05 22:00 -0700
          Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 09:52 +0100
        Re: LLVM and Forth hughaguilar96@gmail.com - 2017-04-06 20:15 -0700
    Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-03 05:20 -0700
      Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-03 17:11 +0100
  Re: LLVM and Forth Alex <alex@rivadpm.com> - 2017-04-06 17:43 +0100
    Re: LLVM and Forth krishna.myneni@ccreweb.org - 2017-04-06 10:53 -0700

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