diff options
| author | Richard Biener <rguenther@suse.de> | 2023-06-26 12:51:37 +0200 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2023-06-26 14:14:54 +0200 |
| commit | 53d6f57c1b20c6da52aefce737fb7d5263686ba3 (patch) | |
| tree | ea464de31dd3bd20324ceb81ea7dd6aa7aa9881d | |
| parent | a024176a97b0176f526862836c33e283b8db4197 (diff) | |
| download | gcc-53d6f57c1b20c6da52aefce737fb7d5263686ba3.zip gcc-53d6f57c1b20c6da52aefce737fb7d5263686ba3.tar.gz gcc-53d6f57c1b20c6da52aefce737fb7d5263686ba3.tar.bz2 | |
tree-optimization/110381 - preserve SLP permutation with in-order reductions
The following fixes a bug that manifests itself during fold-left
reduction transform in picking not the last scalar def to replace
and thus double-counting some elements. But the underlying issue
is that we merge a load permutation into the in-order reduction
which is of course wrong.
Now, reduction analysis has not yet been performend when optimizing
permutations so we have to resort to check that ourselves.
PR tree-optimization/110381
* tree-vect-slp.cc (vect_optimize_slp_pass::start_choosing_layouts):
Materialize permutes before fold-left reductions.
* gcc.dg/vect/pr110381.c: New testcase.
| -rw-r--r-- | gcc/testsuite/gcc.dg/vect/pr110381.c | 40 | ||||
| -rw-r--r-- | gcc/tree-vect-slp.cc | 18 |
2 files changed, 56 insertions, 2 deletions
diff --git a/gcc/testsuite/gcc.dg/vect/pr110381.c b/gcc/testsuite/gcc.dg/vect/pr110381.c new file mode 100644 index 0000000..2313dbf --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr110381.c @@ -0,0 +1,40 @@ +/* { dg-do run } */ + +struct FOO { + double a; + double b; + double c; +}; + +double __attribute__((noipa)) +sum_8_foos(const struct FOO* foos) +{ + double sum = 0; + + for (int i = 0; i < 8; ++i) + { + struct FOO foo = foos[i]; + + /* Need to use an in-order reduction here, preserving + the load permutation. */ + sum += foo.a; + sum += foo.c; + sum += foo.b; + } + + return sum; +} + +int main() +{ + struct FOO foos[8]; + + __builtin_memset (foos, 0, sizeof (foos)); + foos[0].a = __DBL_MAX__; + foos[0].b = 5; + foos[0].c = -__DBL_MAX__; + + if (sum_8_foos (foos) != 5) + __builtin_abort (); + return 0; +} diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc index ab89a82..fee992d 100644 --- a/gcc/tree-vect-slp.cc +++ b/gcc/tree-vect-slp.cc @@ -4673,14 +4673,28 @@ vect_optimize_slp_pass::start_choosing_layouts () m_partition_layout_costs.safe_grow_cleared (m_partitions.length () * m_perms.length ()); - /* We have to mark outgoing permutations facing non-reduction graph - entries that are not represented as to be materialized. */ + /* We have to mark outgoing permutations facing non-associating-reduction + graph entries that are not represented as to be materialized. + slp_inst_kind_bb_reduc currently only covers associatable reductions. */ for (slp_instance instance : m_vinfo->slp_instances) if (SLP_INSTANCE_KIND (instance) == slp_inst_kind_ctor) { unsigned int node_i = SLP_INSTANCE_TREE (instance)->vertex; m_partitions[m_vertices[node_i].partition].layout = 0; } + else if (SLP_INSTANCE_KIND (instance) == slp_inst_kind_reduc_chain) + { + stmt_vec_info stmt_info + = SLP_TREE_REPRESENTATIVE (SLP_INSTANCE_TREE (instance)); + stmt_vec_info reduc_info = info_for_reduction (m_vinfo, stmt_info); + if (needs_fold_left_reduction_p (TREE_TYPE + (gimple_get_lhs (stmt_info->stmt)), + STMT_VINFO_REDUC_CODE (reduc_info))) + { + unsigned int node_i = SLP_INSTANCE_TREE (instance)->vertex; + m_partitions[m_vertices[node_i].partition].layout = 0; + } + } /* Check which layouts each node and partition can handle. Calculate the weights associated with inserting layout changes on edges. */ |