On Thu, 20 Jul 2023, Richard Sandiford wrote: > Richard Biener writes: > >> Am 20.07.2023 um 18:59 schrieb Richard Sandiford : > >> > >> Richard Biener writes: > >>>>> Am 20.07.2023 um 16:09 schrieb Richard Sandiford : > >>>> > >>>> Richard Biener via Gcc-patches writes: > >>>>> When we materialize a layout we push edge permutes to constant/external > >>>>> defs without checking we can actually do so. For externals defined > >>>>> by vector stmts rather than scalar components we can't. > >>>>> > >>>>> Bootstrapped and tested on x86_64-unknown-linux-gnu. > >>>>> > >>>>> OK? > >>>>> > >>>>> Thanks, > >>>>> Richard. > >>>>> > >>>>> PR tree-optimization/110742 > >>>>> * tree-vect-slp.cc (vect_optimize_slp_pass::get_result_with_layout): > >>>>> Do not materialize an edge permutation in an external node with > >>>>> vector defs. > >>>>> (vect_slp_analyze_node_operations_1): Guard purely internal > >>>>> nodes better. > >>>>> > >>>>> * g++.dg/torture/pr110742.C: New testcase. > >>>>> --- > >>>>> gcc/testsuite/g++.dg/torture/pr110742.C | 47 +++++++++++++++++++++++++ > >>>>> gcc/tree-vect-slp.cc | 8 +++-- > >>>>> 2 files changed, 53 insertions(+), 2 deletions(-) > >>>>> create mode 100644 gcc/testsuite/g++.dg/torture/pr110742.C > >>>>> > >>>>> diff --git a/gcc/testsuite/g++.dg/torture/pr110742.C b/gcc/testsuite/g++.dg/torture/pr110742.C > >>>>> new file mode 100644 > >>>>> index 00000000000..d41ac0479d2 > >>>>> --- /dev/null > >>>>> +++ b/gcc/testsuite/g++.dg/torture/pr110742.C > >>>>> @@ -0,0 +1,47 @@ > >>>>> +// { dg-do compile } > >>>>> + > >>>>> +struct HARD_REG_SET { > >>>>> + HARD_REG_SET operator~() const { > >>>>> + HARD_REG_SET res; > >>>>> + for (unsigned int i = 0; i < (sizeof(elts) / sizeof((elts)[0])); ++i) > >>>>> + res.elts[i] = ~elts[i]; > >>>>> + return res; > >>>>> + } > >>>>> + HARD_REG_SET operator&(const HARD_REG_SET &other) const { > >>>>> + HARD_REG_SET res; > >>>>> + for (unsigned int i = 0; i < (sizeof(elts) / sizeof((elts)[0])); ++i) > >>>>> + res.elts[i] = elts[i] & other.elts[i]; > >>>>> + return res; > >>>>> + } > >>>>> + unsigned long elts[4]; > >>>>> +}; > >>>>> +typedef const HARD_REG_SET &const_hard_reg_set; > >>>>> +inline bool hard_reg_set_subset_p(const_hard_reg_set x, const_hard_reg_set y) { > >>>>> + unsigned long bad = 0; > >>>>> + for (unsigned int i = 0; i < (sizeof(x.elts) / sizeof((x.elts)[0])); ++i) > >>>>> + bad |= (x.elts[i] & ~y.elts[i]); > >>>>> + return bad == 0; > >>>>> +} > >>>>> +inline bool hard_reg_set_empty_p(const_hard_reg_set x) { > >>>>> + unsigned long bad = 0; > >>>>> + for (unsigned int i = 0; i < (sizeof(x.elts) / sizeof((x.elts)[0])); ++i) > >>>>> + bad |= x.elts[i]; > >>>>> + return bad == 0; > >>>>> +} > >>>>> +extern HARD_REG_SET rr[2]; > >>>>> +extern int t[2]; > >>>>> +extern HARD_REG_SET nn; > >>>>> +static HARD_REG_SET mm; > >>>>> +void setup_reg_class_relations(void) { > >>>>> + HARD_REG_SET intersection_set, union_set, temp_set2; > >>>>> + for (int cl2 = 0; cl2 < 2; cl2++) { > >>>>> + temp_set2 = rr[cl2] & ~nn; > >>>>> + if (hard_reg_set_empty_p(mm) && hard_reg_set_empty_p(temp_set2)) { > >>>>> + mm = rr[0] & nn; > >>>>> + if (hard_reg_set_subset_p(mm, intersection_set)) > >>>>> + if (!hard_reg_set_subset_p(mm, temp_set2) || > >>>>> + hard_reg_set_subset_p(rr[0], rr[t[cl2]])) > >>>>> + t[cl2] = 0; > >>>>> + } > >>>>> + } > >>>>> +} > >>>>> diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc > >>>>> index 693621ca990..1d79c77e8ce 100644 > >>>>> --- a/gcc/tree-vect-slp.cc > >>>>> +++ b/gcc/tree-vect-slp.cc > >>>>> @@ -5198,7 +5198,10 @@ vect_optimize_slp_pass::get_result_with_layout (slp_tree node, > >>>>> return result; > >>>>> > >>>>> if (SLP_TREE_DEF_TYPE (node) == vect_constant_def > >>>>> - || SLP_TREE_DEF_TYPE (node) == vect_external_def) > >>>>> + || (SLP_TREE_DEF_TYPE (node) == vect_external_def > >>>>> + && (to_layout_i == 0 > >>>>> + /* We can't permute vector defs. */ > >>>>> + || SLP_TREE_VEC_DEFS (node).is_empty ()))) > >>>> > >>>> Guess it's personal preference, but IMO it's easier to follow without the > >>>> to_layout_i condition, so that it ties directly to the create_partitions > >>>> test. > >>> > >>> I don?t understand- in the code guarding this we seem to expect to_layout_i == 0 and that?s the case we can handle as noop. I didn?t understand why the function doesn?t always just do nothing in this case though, so I must have missed something. > >> > >> OK, so I guess that disproves that my way is easier to understand :) > >> > >> I think logically, the code is doing the equivalent of: > >> > >> int partition_i = m_vertices[node->vertex].partition; > >> if (partition < 0) > >> { > >> /* If the vector is uniform or unchanged, there's nothing to do. */ > >> ... > >> } > >> else > >> { > >> ... Return node if to_layout_i matches this partition's chosen layout... > >> } > >> > >> And I guess I should have written it that way. > >> > >> So when there is no partition, we have a constant or external def > >> built from individual scalars. We can use the node as-is if the > >> caller wants an unpermuted node or if all elements are equal > >> (so that the permutation doesn't matter). Otherwise we need > >> to permute the scalars. > >> > >> When there is a partition, we can use the node as-is if the caller > >> wants the layout that was chosen for that partition. Otherwise we > >> need a new VEC_PERM_EXPR node. > >> > >> In the particular case of external defs built from vectors, we're > >> guaranteed that the node's chosen layout is 0 (i.e. the original layout), > >> and so both ways work. > > > > Hmm, but I arrived here with that not being the case ? (the chosen Lay-out not zero) > > By chosen layout for the partition, I meant: > > unsigned int from_layout_i = m_partitions[partition_i].layout; > > That should be 0 for these external vector nodes due to the > start_choosing_layout code that you mentioned in the PR. to_layout_i > (the layout that the caller wants for a use of the node) can be anything, > so yeah, to_layout_i != 0 has to go through the "else" arm and generate > a VEC_PERM_EXPR. But because from_layout_i == 0 for these nodes, > the "else" arm should handle all cases correctly, not just the > to_layout_i != 0 case. Ah, yes - of course. I'll remove the extra test, re-test and push. Thanks, Richard.