This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: MEM_COPY_ATTRIBUTES
- To: kenner at vlsi1 dot ultra dot nyu dot edu
- Subject: Re: MEM_COPY_ATTRIBUTES
- From: Mark Mitchell <mark at codesourcery dot com>
- Date: Wed, 03 May 2000 08:38:50 -0700
- Cc: gcc at gcc dot gnu dot org
- Organization: CodeSourcery, LLC
- References: <10005031448.AA26299@vlsi1.ultra.nyu.edu>
>>>>> "Richard" == Richard Kenner <kenner@vlsi1.ultra.nyu.edu> writes:
Richard> Is there a reason it doesn't copy MEM_ALIAS_SET?
Yes. Look for places where MEM_COPY_ATTRIBUTES is used but
MEM_ALIAS_SET is not. They should represent places where the
resulting memory doesn't have the same type as the original memory.
(For example, the new MEM might not point at the same location as the
old MEM, or might be wider.)
It's very important to be conservative in this respect, lest very hard
to find bugs appear. So, I was. If you find places where you think
the MEM_ALIAS_SET should be copied, you might be right -- but you
should be very careful. For example, consider an alias set that
indicates a structure. You have to consider alias subsets and
supersets as well.
--
Mark Mitchell mark@codesourcery.com
CodeSourcery, LLC http://www.codesourcery.com