Re: optimization/8300: [3.2/3.3/3.4 regression] [sparc] ICE in gen_reg_rtx, at emit-rtl.c:662

[Andreas Schwab <schwab@suse.de>]

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The following reply was made to PR optimization/8300; it has been noted by GNATS.

From: Andreas Schwab <schwab@suse.de>
To: Robert Schiele <rschiele@uni-mannheim.de>
Cc: Richard Henderson <rth@redhat.com>, gcc-bugs@gcc.gnu.org,
	tneumann@pi3.informatik.uni-mannheim.de, gcc-gnats@gcc.gnu.org
Subject: Re: optimization/8300: [3.2/3.3/3.4 regression] [sparc] ICE in
 gen_reg_rtx, at emit-rtl.c:662
Date: Mon, 17 Mar 2003 16:34:38 +0100

 Robert Schiele <rschiele@uni-mannheim.de> writes:
 
 |> On Mon, Mar 17, 2003 at 09:29:37AM -0500, Daniel Jacobowitz wrote:
 |> > If you have a copy of the standard, it's 6.5.6#8.  Once a pointer is
 |> > adjusted to point outside of the original object it must not be
 |> > dereferenced.  Accessing memory in this way produces undefined
 |> > behavior.
 |> 
 |> Ok thanks, found it there.
 |> 
 |> How about this:
 |> 
 |> void a() {
 |>     double b;
 |>     int c[2];
 |>     *((int*)&b) && (c[1] = 0);
 |> }
 |> 
 |> Exactly same problem.  And this time there is no pointer outside well
 |> defined data area.  You agree that this sample is legal code?
 
 Ignoring the missing initialisation of b this is undefined under the
 aliasing rules.
 
 Andreas.
 
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 Andreas Schwab, SuSE Labs, schwab@suse.de
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