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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
> code.
>
No, they are not. Syd's test case with pointer dereferences is not
something you can solve with an FE hook.
Diego.