From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Edelsohn To: Mark Mitchell Cc: rms@gnu.org, jbuck@synopsys.com, mrs@wrs.com, gcc@gcc.gnu.org Subject: Re: type based aliasing again Date: Thu, 30 Sep 1999 18:02:00 -0000 Message-ID: <9909120057.AA36240@marc.watson.ibm.com> References: <19990911152505P.mitchell@codesourcery.com> X-SW-Source: 1999-09n/msg00446.html Message-ID: <19990930180200.ttcnvxeUcm92Tf-bvFw1Uwpmqinm40yDngwEWGiE4wA@z> >>>>> Mark Mitchell writes: Mark> I think that making -fno-strict-aliasing the default is sensible Mark> proposal, and worth debating. Mark> I would much rather see us change the default, if that is really Mark> necessary, than muddy the waters with confusing semantics, semantics Mark> that will change due to minor adjustments to the compiler. Yes, this Mark> would mean that users cannot have their cake and eat it too: they Mark> cannot have the benefits of -fstrict-alaising and still not follow the Mark> ISO rules. But, they are no worse off than before we added the Mark> aliasing optimizations. FYI, IBM's AIX compiler does not enable "ANSI aliasing" by default when the compiler is invoked with "cc". AIX "cc" essentially is "gcc -fno-strict-alias -fwriteable-strings"; AIX "xlc" command enables alias optimizations and creates read-only constants. David