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Re: Help restricting args of an intrinsic function
- From: Diego Novillo <dnovillo at redhat dot com>
- To: Mike Stump <mrs at apple dot com>
- Cc: Syd Polk <spolk at apple dot com>, GCC List <gcc at gcc dot gnu dot org>
- Date: Sat, 31 Jan 2004 10:25:13 -0500
- Subject: Re: Help restricting args of an intrinsic function
- Organization: Red Hat Canada
- References: <72958959-53BB-11D8-9B07-003065BDF310@apple.com>
On Sat, 2004-01-31 at 02:02, Mike Stump wrote:
> > Syd's problem can only be addressed if you have some
> > minimal data flow information available.
> No. Enumeration constants don't require data flow. Intergral constant
> expressions don't require data flow.
Syd seems to be looking for anything that the compiler can prove is a
constant. Realizing that a pointer dereference is a compile time
constant *does* need dataflow info, however trivial.
> I don't think Syd needs anything
> as powerful as dataflow, just as powerful as fold.
Powerful != expensive. Why are you considering such a simple data flow
problem a non-starter?
> The problem is
> these are frontend concepts and they may need to be handled by frontend
No, they are not. Syd's test case with pointer dereferences is not
something you can solve with an FE hook.