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

[Robert Schiele <rschiele@uni-mannheim.de>]

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

From: Robert Schiele <rschiele@uni-mannheim.de>
To: Richard Henderson <rth@redhat.com>, rth@gcc.gnu.org, gcc-bugs@gcc.gnu.org,
   gcc-prs@gcc.gnu.org, nobody@gcc.gnu.org,
   tneumann@pi3.informatik.uni-mannheim.de, gcc-gnats@gcc.gnu.org
Cc:  
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 10:25:04 +0100

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 On Mon, Mar 17, 2003 at 01:05:55AM -0800, Richard Henderson wrote:
 > On Mon, Mar 17, 2003 at 06:08:21AM +0100, Robert Schiele wrote:
 > > *(&c + 1) is also well defined.
 >=20
 > How's that?
 
 It's pointer arithmetic:
 
 Assume you have the following memory layout...
 
 |   |
 +---+
 |   | <=3D=3D ... then the contents of that address is *(&c + 1)
 +---+
 | c |
 +---+
 |   |
 
 It is:
 
 c: The contents of the variable c on the stack.
 
 &c: The address where c is located on the stack.
 
 &c + 1: That address plus 4 byte. (sizeof(int) =3D=3D 4 on sparc)
 
 *(&c + 1): The contents of the above address.
 
 > > 1. My rewritten example is legal code with no doubt and produces an
 > >    ICE whit optimization.
 >=20
 > Nyet.
 
 Well, I still don't see why this is illegal. Can you give me the
 paragraph of the C standard that prohibits this sort of pointer
 arithmetic?
 
 Robert
 
 --=20
 Robert Schiele			Tel.: +49-621-181-2517
 Dipl.-Wirtsch.informatiker	mailto:rschiele@uni-mannheim.de
 
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