target/3506: weird behaviour when incrementing volatile ints

[Herbert Xu]

The following reply was made to PR target/3506; it has been noted by GNATS.

From: Herbert Xu <herbert@gondor.apana.org.au>
To: rth@gcc.gnu.org, 89949-quiet@bugs.debian.org, gcc-bugs@gcc.gnu.org,
	gcc-prs@gcc.gnu.org, nobody@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Cc:  
Subject: Re: target/3506: weird behaviour when incrementing volatile ints
Date: Wed, 3 Apr 2002 20:29:27 +1000

 On Fri, Mar 29, 2002 at 10:42:35AM -0000, rth@gcc.gnu.org wrote:
 > Synopsis: weird behaviour when incrementing volatile ints
 > 
 > State-Changed-From-To: open->closed
 > State-Changed-By: rth
 > State-Changed-When: Fri Mar 29 02:42:35 2002
 > State-Changed-Why:
 >     GCC doesn't know what constitutes a reference to a volatile memory,
 >     so it never performs operations on them directly.  It will always
 >     pull the value into a register first.
 
 This breaks C99 wrt sig_atomic_t.  The increment has to be a single
 instruction.
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