From b2f26af32b5b031fce761aa090de9476a53e6e5a Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Wed, 20 May 2020 09:22:58 +0200 Subject: [PATCH] tree-optimization/95219 - improve IV selection for induction This improves code generation with SSE2 for the testcase by making sure to only generate a single IV when the group size is a multiple of the vector size. It also adjusts the testcase which was passing before. 2020-05-20 Richard Biener PR tree-optimization/95219 * tree-vect-loop.c (vectorizable_induction): Reduce group_size before computing the number of required IVs. * gcc.dg/vect/costmodel/x86_64/costmodel-pr30843.c: Adjust. --- gcc/ChangeLog | 6 ++++++ gcc/testsuite/ChangeLog | 6 ++++++ .../vect/costmodel/x86_64/costmodel-pr30843.c | 4 +++- gcc/tree-vect-loop.c | 14 +++++++++++++- 4 files changed, 28 insertions(+), 2 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2eba6db9a91..88b03be7135 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2020-05-20 Richard Biener + + PR tree-optimization/95219 + * tree-vect-loop.c (vectorizable_induction): Reduce + group_size before computing the number of required IVs. + 2020-05-20 Richard Biener PR middle-end/95231 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 3d63c57f308..9552d201b5e 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2020-05-20 Richard Biener + + PR tree-optimization/95219 + * tree-vect-loop.c (vectorizable_induction): Reduce + group_size before computing the number of required IVs. + 2020-05-20 Richard Biener PR middle-end/95231 diff --git a/gcc/testsuite/gcc.dg/vect/costmodel/x86_64/costmodel-pr30843.c b/gcc/testsuite/gcc.dg/vect/costmodel/x86_64/costmodel-pr30843.c index 257d098cf8b..9a75b987d6d 100644 --- a/gcc/testsuite/gcc.dg/vect/costmodel/x86_64/costmodel-pr30843.c +++ b/gcc/testsuite/gcc.dg/vect/costmodel/x86_64/costmodel-pr30843.c @@ -20,4 +20,6 @@ void dacP98FillRGBMap (unsigned char *pBuffer) } } -/* { dg-final { scan-tree-dump-times "vectorization not profitable" 1 "vect" { target vect_interleave } } } */ +/* Even with SSE2 we should only generate one IV for the induction. */ +/* { dg-final { scan-tree-dump-times "# vect_vec_iv" 1 "vect" } } */ +/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */ diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index f065acc12f5..ecce348b39c 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -7528,7 +7528,13 @@ vectorizable_induction (loop_vec_info loop_vinfo, unsigned group_size = SLP_TREE_SCALAR_STMTS (slp_node).length (); unsigned nvects = SLP_TREE_NUMBER_OF_VEC_STMTS (slp_node); unsigned elts = const_nunits * nvects; - unsigned nivs = least_common_multiple (group_size, + /* Compute the number of distinct IVs we need. First reduce + group_size if it is a multiple of const_nunits so we get + one IV for a group_size of 4 but const_nunits 2. */ + unsigned group_sizep = group_size; + if (group_sizep % const_nunits == 0) + group_sizep = group_sizep / const_nunits; + unsigned nivs = least_common_multiple (group_sizep, const_nunits) / const_nunits; gcc_assert (elts % group_size == 0); tree elt = init_expr; @@ -7576,6 +7582,12 @@ vectorizable_induction (loop_vec_info loop_vinfo, SLP_TREE_VEC_STMTS (slp_node).quick_push (induction_phi_info); } + /* Fill up to the number of vectors we need for the whole group. */ + nivs = least_common_multiple (group_size, + const_nunits) / const_nunits; + for (; ivn < nivs; ++ivn) + SLP_TREE_VEC_STMTS (slp_node) + .quick_push (SLP_TREE_VEC_STMTS (slp_node)[0]); /* Re-use IVs when we can. */ if (ivn < nvects) -- 2.30.2