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

[Robert Schiele <rschiele at uni-mannheim dot de>]

On Mon, Mar 17, 2003 at 04:24:34PM +0100, Falk Hueffner wrote:
> Robert Schiele <rschiele at uni-mannheim dot de> writes:
> 
> > 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?
> 
> No, you're violating the rule in 6.5.7 by accessing an object of type
> double with an lvalue of type int.

6.5.7?  This one is about bitwise shift operators in
	ISO/IEC 9899:1999.  There is no bitwise shift operator in my
	expression.

lvalue?  b is not used as an lvalue here, is it?

Is it generally illegal to do a cast of this type?

Is it just illegal, because double has 8 bytes, where int has 4 on
this platform?  In that case change double to float which has also 4
byte. ==> Same problem.

I can't find such a limitation in 6.5.4 Cast operators.  Is there such
a limit somewhere?

Additional note: The code compiles fine when the declaration of b has
a volatile qualifier.

Robert

-- 
Robert Schiele			Tel.: +49-621-181-2517
Dipl.-Wirtsch.informatiker	mailto:rschiele at uni-mannheim dot de

Attachment: pgp00000.pgp
Description: PGP signature