This is the mail archive of the
mailing list for the GCC project.
Re: [PATCH] Support for known unknown alignment
- From: Jay Foad <jay dot foad at gmail dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 20 Apr 2012 19:41:24 +0100
- Subject: Re: [PATCH] Support for known unknown alignment
- References: <20120420155409.GC24038@virgil.arch.suse.de>
On 20 April 2012 16:54, Martin Jambor <email@example.com> wrote:
> two days ago I talked to Richi on IRC about the functions to determine
> the expected alignment of objects and pointers we have and he
> suggested that get_object_alignment_1 and get_pointer_alignment_1
> should return whether the alignment is actually known
Can you explain how returning "unknown" is different from returning
some minimal known alignment? Comments like:
> ! /* Compute values M and N such that M divides (address of EXP - N) and
> ! Â Âsuch that N < M. ÂStore N in *BITPOSP and return M.
suggest that M=1, N=0 is always a valid conservative thing to return.
If there is a difference, the comment should explain what it means.