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Re: RFC: merging MEM_ATTRS
- From: Joern Rennecke <joern dot rennecke at superh dot com>
- To: kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)
- Cc: joern dot rennecke at superh dot com, gcc at gcc dot gnu dot org
- Date: Tue, 10 Feb 2004 19:56:58 +0000 (GMT)
- Subject: Re: RFC: merging MEM_ATTRS
> No. You need this whever you haven't bothered to set MEM_ATTRS. There's
> absolutely no requirement that all MEM's have it set and there are lots
> of cases where they don't. Are you proposing to treat each of them as bugs?
I can see how it gets problematic when we have such code. So we must record
the information that we know. In order to make the information in MEM_EXPR
useful for alias analysis purposes, that means when we have a pointer
dereference or array access, instead of punting and putting NULL_TREE
there, we can use a special marker tree there (preferrably a shared one)
that says that some indirection is involved at source-code level,
and hence this can't mean any variable that didn't have its address taken.