On Tue, Sep 30, 2014 at 11:59 AM, Bin Cheng <bin.ch...@arm.com> wrote: > Hi, > As analyzed in PR62178, IVOPT can't find the optimal iv set for that case. > The problem with current heuristic algorithm is it only replaces candidate > with ones not in current solution one by one, starting from small solution. > This patch adds another heuristic which starts from assigning the best > candidate for each iv use, then replaces candidate with ones in the current > solution. > Before this patch, there are two runs of find_optimal_set_1 to find the > optimal iv sets, we name them as set_a and set_b. After this patch we will > have set_c. At last, IVOPT chooses the best one from set_a/set_b/set_c. To > prove that this patch is necessary, I collected instrumental data for gcc > bootstrap, spec2k, eembc and can confirm for some cases only the newly added > heuristic can find the optimal iv set. The number of these cases in which > set_c is the optimal one is on the same level of set_b. > As for the compilation time, the newly added function actually is one > iteration of previous selection algorithm, it should be much faster than > previous process. > > I also added one target dependent test case. > Bootstrap and test on x86_64, test on aarch64. Any comments?
Ok. Thanks, Richard. > 2014-09-30 Bin Cheng <bin.ch...@arm.com> > > PR tree-optimization/62178 > * tree-ssa-loop-ivopts.c (enum sel_type): New. > (iv_ca_add_use): Add parameter RELATED_P and find the best cand > for iv use if it's true. > (try_add_cand_for, get_initial_solution): Change paramter ORIGINALP > to SELECT_TYPE and handle it. > (find_optimal_iv_set_1): Ditto. > (try_prune_iv_set, find_optimal_iv_set_2): New functions. > (find_optimal_iv_set): Call find_optimal_iv_set_2 and choose the > best candidate set. > > gcc/testsuite/ChangeLog > 2014-09-30 Bin Cheng <bin.ch...@arm.com> > > PR tree-optimization/62178 > * gcc.target/aarch64/pr62178.c: New test.
