Re: [patch] builtins.c, fold-const.c: Don't create type

[Mark Mitchell <mark at codesourcery dot com>]

Steven Bosscher wrote:

> On IRC, Chris Lattner mentioned (if I understood him correctly) that in
> LLVM this kind of pointer arithmetic doesn't exist, and that instead it
> is converted to "regular" integer arithmatic by casting the pointer to
> intptr_t (instead of casting the integer to a pointer).  Would that be
> a better solution for GCC too, perhaps?

It will not be fun to support 32-bit pointers on Itanium or PA with 
LLVM, as integer arithmetic does not quite do the right thing.  You have 
to fiddle with high-order bits in the pointer as well, so you would have 
to insert explicit shift/mask operations.  In order to get good code, 
you have to generate "addp4" rather than just integer addition, and that 
means keeping track of what's a pointer and what isn't.

--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com
(916) 791-8304