On Tue, 23 Jan 2024, Jakub Jelinek wrote: > On Tue, Jan 23, 2024 at 12:56:52PM +0100, Richard Biener wrote: > > The following avoids using exact_log2 on the number of SIMD clone calls > > to be emitted when vectorizing calls since that can easily be not > > a power of two in which case it will return -1. For different simd > > clones the number of calls will differ by a multiply with a power of two > > only so using floor_log2 is good enough here. > > > > Bootstrap and regtest running on x86_64-unknown-linux-gnu. > > > > PR tree-optimization/113552 > > * tree-vect-stmts.cc (vectorizable_simd_clone_call): Use > > floor_log2 instead of exact_log2 on the number of calls. > > Is there any target which supports non-power-of-two simdlen? > If not, perhaps we should add !pow2p_hwi (num_calls) to the continue; > condition a few lines earlier?
Is non-power-of-two simdlen a thing? Note there's nothing wrong with non-power-of-two num_calls, with VF == 4 and a group size of 3 you get 12 lanes and either 3 (simdlen == 4) or 6 (simdlen == 2) calls. Iff non-power-of-two simdlen is a thing then we could bias by + num_calls (no idea why we use *_log2 in the first place, but it was that way since the beginning). Richard. > > diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc > > index 09749ae3817..1dbe1115da4 100644 > > --- a/gcc/tree-vect-stmts.cc > > +++ b/gcc/tree-vect-stmts.cc > > @@ -4071,7 +4071,7 @@ vectorizable_simd_clone_call (vec_info *vinfo, > > stmt_vec_info stmt_info, > > || (nargs != simd_nargs)) > > continue; > > if (num_calls != 1) > > - this_badness += exact_log2 (num_calls) * 4096; > > + this_badness += floor_log2 (num_calls) * 4096; > > if (n->simdclone->inbranch) > > this_badness += 8192; > > int target_badness = targetm.simd_clone.usable (n); > > -- > > 2.35.3 > > Jakub > > -- Richard Biener <rguent...@suse.de> SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg, Germany; GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
