Re: toolchain/40694: gcc tail-call vs. volatile bug

[David Laight <david%l8s.co.uk@localhost>]

The following reply was made to PR toolchain/40694; it has been noted by GNATS.

From: David Laight <david%l8s.co.uk@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: toolchain/40694: gcc tail-call vs. volatile bug
Date: Thu, 19 Feb 2009 20:59:58 +0000

 On Thu, Feb 19, 2009 at 06:00:00PM +0000, dholland%eecs.harvard.edu@localhost 
wrote:
 > >Number:         40694
 > >Category:       toolchain
 > >Synopsis:       gcc tail-call vs. volatile bug
 ...
 > Compiling the following fragment (gcc -O2 -S foo.c) generates an
 > invalid tail call that does not repeat the local (volatile, no less)
 > variable on a new stack frame.
 > 
 > void
 > recurse_inf(void)
 > {
 >    volatile char buf[16];
 >    buf[0] = 0;
 >    recurse_inf();
 > }
 
 Surely the 'as if' rule applies?
 Since 'buf' cannot be referenced it can be discarded.
 I don't see why the 'volatile' would have any effect here.
 
        David
 
 -- 
 David Laight: david%l8s.co.uk@localhost