From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael P. Hayes" To: Joern Rennecke Cc: michaelh@ongaonga.chch.cri.nz (Michael P. Hayes), law@cygnus.com, Franz.Sirl-kernel@lauterbach.com, mark@markmitchell.com, egcs@cygnus.com Subject: Re: Alias code Date: Wed, 01 Jul 1998 00:54:00 -0000 Message-id: <199807010023.AAA23563@ongaonga.chch.cri.nz> References: <199806301022.KAA20139@ongaonga.chch.cri.nz> <199806301840.TAA04463@phal.cygnus.co.uk> X-SW-Source: 1998-07/msg00017.html Joern Rennecke writes: > > While on the alias code subject, EGCS could do with a mechanism so > > that a programmer can hint to the compiler that a memory reference is > > to a different address space, say an internal memory block. The > > backend could then do a better scheduling job by knowing that the > > memory access is likely to be faster than normal and that it won't > > conflict with an external memory access. Any ideas? > > We'd need yet another field in the MEM to represent that. Yes, but how would we inform the front-end to set this flag? Ideally, C needs another qualifer like fast or internal to say that a pointer is likely to be referring to something in internal memory. It probably should be more general to deal with processors, in particular DSPs, that have multiple address spaces that the compiler needs to be aware of when generating fast code. Does anyone know how the SHARC port deals with this? > Well, if we have that, then the md file can describe the stuff to the > scheduler by claiming to use different function units depending on > the address space. Yes, that's one aspect I was thinking of. I was also hoping to use the flag during RTL generation. Michael.