On August 25, 2017 12:25:57 AM GMT+02:00, Jeff Law <l...@redhat.com> wrote: >On 08/14/2017 03:19 AM, Bin Cheng wrote: >> HI, >> This patch adds copying interface for dependence_info. The >methodology >> is we don't copy such information by default, and this interface >should >> be called explicitly when it is safe and necessary to do so. Just >like >> this patch uses the interface in ivopts. >> Bootstrap and test in series. Is it OK? >> >> Thanks, >> bin >> 2017-08-10 Bin Cheng <bin.ch...@arm.com> >> >> * tree-ssa-address.c (copy_dependence_info): New function. >> * tree-ssa-address.h (copy_dependence_info): New declaration. >> * tree-ssa-loop-ivopts.c (rewrite_use_address): Call above func. >So do we have any structure sharing assumptions on the alias >structures? >ie, are we setting up the possibility that these objects will be shared >and that someone will modify them in a way that works in one context, >but not another? > >If they're readonly after creation, then obviously this isn't a >concern. > >I wouldn't consider this an object or an ACK for the patch at this >point. More a design question we need to answer.
Note there are existing places where we copy the info. Note that for example the inliner re-maps the cliques during copying to not introduce false non-dependennces This is another possibility to avoid the issue with unrolling. Richard. >Jeff
