From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerald Pfeifer To: David Edelsohn Cc: Nick Ing-Simmons , richard.earnshaw@arm.com, N8TM@aol.com, gcc@gcc.gnu.org, Marc Espie Subject: Re: type based aliasing again Date: Thu, 30 Sep 1999 18:02:00 -0000 Message-ID: References: <9909141752.AA20924@marc.watson.ibm.com> X-SW-Source: 1999-09n/msg00553.html Message-ID: <19990930180200.cEhsmFFVZ4bmsKOUXgOpQlupTLDHK5WTankg7jIpS_M@z> Some time ago, Mark wrote: | Saying "Don't violate ANSI/ISO aliasing rules, or else use | -fno-strict-aliasing" is a simple, easy-to-follow rule. and don't really see why this shouldn't be viable. On Tue, 14 Sep 1999, David Edelsohn wrote: > I think that GCC should make this simple change. Instead of removing a nice and rather stable optimization for the sake of compiling broken code, why can't we 1. implement warnings; 2. document the issue in the FAQ and describe the simple workaround of using fno-aliasing; 3. wait what really happens? What I *really* wonder is: If this is breaking that much legacy code, where are the bug reports? After the GCC 2.95.x releases we had quite a couple of reports concerning problems on Solaris, but I cannot remember a single one concerning the aliasing issue! Apart from OpenBSD which seems to have encountered a real bug, just Perl and Linux have been mentioned (both of which are actively maintained). Gerald -- Gerald "Jerry" pfeifer@dbai.tuwien.ac.at http://www.dbai.tuwien.ac.at/~pfeifer/