On Fri, Jun 19, 2015 at 7:04 PM, Charles Baylis <charles.bay...@linaro.org> wrote: > On 18 June 2014 at 11:06, Ramana Radhakrishnan > <ramana....@googlemail.com> wrote: >> On Tue, Jun 17, 2014 at 4:03 PM, Charles Baylis >> <charles.bay...@linaro.org> wrote: >>> Your mention of larger vector modes prompted me to check that the >>> patch has the desired result with them. In fact, the costs are >>> estimated incorrectly which means the post_modify pattern is not used. >>> The attached patch fixes that. (used in combination with my original >>> patch) >>> >>> >>> 2014-06-15 Charles Baylis <charles.ba...@linaro.org> >>> >>> * config/arm/arm.c (arm_new_rtx_costs): Reduce cost for mem with >>> embedded side effects. >> >> I'm not too thrilled with putting in more special cases that are not >> table driven in there. Can you file a PR with some testcases that show >> this so that we don't forget and CC me on it please ? > > I created https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61551 at the time. > > I've come back to look at this again and would like to fix it in this > release cycle. I still don't really understand what you mean by > table-driven in this context. Do you still hold this view, and if so, > could you describe what you'd like to see instead of this patch?
By table-driven I mean something similar to the existing rtx_costs infrastructure with a walker and a data structure holding costs for each addressing mode which are tweakable on a per-core basis. Thus for example I'd expect this to be on a per access mode basis along with different costs with respect to post_inc, reg indirect, pre_inc etc. that were in a data structure and then a worker function that peeled rtx's to obtain the appropriate cost from said data-structure. Ramana
