Hi Jeff, Thanks for your help.
Actually I have write access as I was added to the "contributor list". Anyway, that's very kind of you to help committing the patch. Thanks, -Hao ________________________________________ From: Jeff Law <jeffreya...@gmail.com> Sent: Friday, July 7, 2023 0:06 To: Richard Biener; Hao Liu OS Cc: GCC-patches@gcc.gnu.org Subject: Re: [PATCH] Vect: use a small step to calculate induction for the unrolled loop (PR tree-optimization/110449) On 7/6/23 06:44, Richard Biener via Gcc-patches wrote: > On Wed, Jul 5, 2023 at 8:44 AM Hao Liu OS via Gcc-patches > <gcc-patches@gcc.gnu.org> wrote: >> >> Hi, >> >> If a loop is unrolled by n times during vectoriation, two steps are used to >> calculate the induction variable: >> - The small step for the unrolled ith-copy: vec_1 = vec_iv + (VF/n * Step) >> - The large step for the whole loop: vec_loop = vec_iv + (VF * Step) >> >> This patch calculates an extra vec_n to replace vec_loop: >> vec_n = vec_prev + (VF/n * S) = vec_iv + (VF/n * S) * n = vec_loop. >> >> So that we can save the large step register and related operations. > > OK. It would be nice to avoid the dead stmts created earlier though. > > Thanks, > Richard. > >> gcc/ChangeLog: >> >> PR tree-optimization/110449 >> * tree-vect-loop.cc (vectorizable_induction): use vec_n to replace >> vec_loop for the unrolled loop. >> >> gcc/testsuite/ChangeLog: >> >> * gcc.target/aarch64/pr110449.c: New testcase. I didn't see Hao Liu in the MAINTAINERS file, so probably doesn't have write access. Therefore I went ahead and pushed this for Hao. jeff
