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[Bug middle-end/49721] convert_memory_address_addr_space may generate invalid new insns
- From: "hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 28 Jul 2011 21:40:11 +0000
- Subject: [Bug middle-end/49721] convert_memory_address_addr_space may generate invalid new insns
- Auto-submitted: auto-generated
- References: <bug-49721-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49721
--- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> 2011-07-28 21:39:47 UTC ---
(In reply to comment #3)
> (In reply to comment #2)
> > The question is we have
> >
> > (zero_extend:DI (plus:SI (FOO:SI) (const_int Y)))
> >
> > Is is OK to transform it to
> >
> > (plus:DI (zero_extend:DI (FOO:SI)) (const_int Y))
>
> It is valid if addresses can never extend across singed SI_MAX and SI_MIN.
For POINTERS_EXTEND_UNSIGNED > 0, the valid address arrange is
0 to UINT_MAX.