From: dewar@gnat.com (Robert Dewar)
To: dewar@gnat.com, segher@koffie.nl
Cc: bosch@gnat.com, gcc-patches@gcc.gnu.org, gcc@gcc.gnu.org,
kenner@vlsi1.ultra.nyu.edu
Subject: Re: [PATCH] Document arithmetic overflow semantics
Date: Sun, 16 Feb 2003 16:17:00 -0000 [thread overview]
Message-ID: <20030216124140.1F6D8F2D53@nile.gnat.com> (raw)
> Yes, but won't such a program always give a compile-time
> warning like "this branch will never be executed" or
> "unreachable code deleted"? Can you give an example
> where the compiler will delete a branch but where it
> is not able to diagnose it did?
Actually it is often very difficult to track down actions in a complex
optimization circuit that is manipulating some intermediate form to give
clear diagnostics, because the sequence of logic that arrives at a decision
may be arbitrarily complex, and it may be difficult for instance o tell
if the code in question is a direct consequence of the original source
code, or some code generated by some other optimization. Certainly there
is no requirement for a compiler to give such warnings.
next reply other threads:[~2003-02-16 12:41 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-02-16 16:17 Robert Dewar [this message]
2003-02-18 6:41 ` Segher Boessenkool
2003-02-18 6:49 ` Fergus Henderson
2003-02-18 18:13 ` Joe Buck
-- strict thread matches above, loose matches on Subject: below --
2003-02-14 15:26 Robert Dewar
2003-02-14 14:58 Richard Kenner
2003-02-14 14:24 Robert Dewar
2003-02-16 5:52 ` Segher Boessenkool
2003-02-14 14:14 Richard Kenner
2003-02-14 5:57 Robert Dewar
2003-02-14 6:43 ` Chris Lattner
2003-02-14 18:14 ` Joe Buck
2003-02-14 4:48 Robert Dewar
2003-02-13 21:14 Robert Dewar
2003-02-13 21:01 Chris Lattner
2003-02-14 8:17 ` Marcel Cox
2003-02-14 18:23 ` Joe Buck
2003-02-14 18:51 ` Nathan Sidwell
2003-02-13 20:41 Robert Dewar
2003-02-13 20:35 Robert Dewar
2003-02-13 20:14 Robert Dewar
2003-02-13 19:59 Robert Dewar
2003-02-13 19:42 Robert Dewar
2003-02-13 19:31 Robert Dewar
2003-02-13 19:22 Robert Dewar
2003-02-13 19:47 ` Joe Buck
2003-02-13 19:19 Robert Dewar
2003-02-13 19:56 ` Fergus Henderson
2003-02-13 19:10 Robert Dewar
2003-02-14 8:00 ` Fergus Henderson
2003-02-14 8:44 ` Fergus Henderson
2003-02-14 17:29 ` Michael S. Zick
2003-02-13 19:08 Robert Dewar
2003-02-13 19:23 ` Fergus Henderson
2003-02-13 19:32 ` Andrew Haley
2003-02-13 19:03 Richard Kenner
2003-02-13 18:58 Robert Dewar
2003-02-13 19:04 ` Andrew Haley
2003-02-13 20:55 ` Neil Booth
2003-02-13 21:10 ` Gabriel Dos Reis
2003-02-14 4:45 ` Phil Edwards
2003-02-14 8:46 ` Diego Novillo
2003-02-13 18:54 Robert Dewar
2003-02-13 18:53 Robert Dewar
2003-02-13 18:50 Robert Dewar
2003-02-13 18:33 Richard Kenner
2003-02-13 18:29 Richard Kenner
2003-02-13 18:29 Richard Kenner
2003-02-13 18:56 ` Roger Sayle
2003-02-13 19:07 ` Joe Buck
2003-02-13 18:21 Robert Dewar
2003-02-13 22:04 ` Florian Weimer
2003-02-13 23:03 ` Joseph S. Myers
2003-02-15 20:52 ` Mark Hahn
2003-02-15 21:15 ` Neil Booth
2003-02-13 17:54 Richard Kenner
2003-02-13 16:21 Richard Kenner
2003-02-13 17:59 ` Roger Sayle
2003-02-13 16:09 Richard Kenner
2003-02-13 17:49 ` Joe Buck
2003-02-13 16:09 Richard Kenner
2003-02-13 15:58 Richard Kenner
2003-02-13 16:10 ` Roger Sayle
2003-02-13 17:05 ` Joseph S. Myers
2003-02-13 18:05 ` Richard Henderson
2003-02-13 18:15 ` Richard Earnshaw
2003-02-13 19:03 ` Richard Henderson
2003-02-13 18:25 ` Roger Sayle
2003-02-13 18:44 ` Andrew Haley
2003-02-13 19:06 ` Richard Henderson
2003-02-13 15:52 Richard Kenner
2003-02-13 16:03 ` Roger Sayle
2003-02-13 15:45 Richard Kenner
2003-02-13 15:35 Richard Kenner
2003-02-13 15:57 ` Roger Sayle
2003-02-13 15:33 Richard Kenner
2003-02-13 15:36 ` Gabriel Dos Reis
2003-02-13 15:45 ` Roger Sayle
2003-02-13 15:23 Richard Kenner
2003-02-13 14:57 Richard Kenner
2003-02-13 14:58 ` Gabriel Dos Reis
2003-02-13 15:26 ` Roger Sayle
2003-02-13 16:42 ` Joseph S. Myers
2003-02-13 17:58 ` Richard Henderson
2003-02-13 18:16 ` Roger Sayle
2003-02-13 19:46 ` Erik Trulsson
2003-02-13 13:24 Richard Kenner
2003-02-13 14:44 ` Roger Sayle
2003-02-13 18:39 ` Fergus Henderson
2003-02-13 19:05 ` Joe Buck
2003-02-14 13:52 ` Richard Earnshaw
2003-02-13 22:37 ` Richard Henderson
2003-02-13 22:54 ` Roger Sayle
2003-02-13 22:56 ` David Carlton
2003-02-14 0:11 ` Nathan Sidwell
2003-02-14 7:20 ` Fergus Henderson
2003-02-14 13:58 ` Geert Bosch
2003-02-14 18:59 ` Joseph S. Myers
2003-02-14 19:37 ` Joseph S. Myers
2003-02-13 16:04 ` Joe Buck
2003-02-13 16:22 ` Richard Earnshaw
2003-02-13 21:47 ` Florian Weimer
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