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authorRichard Biener <rguenther@suse.de>2021-02-04 12:08:47 +0100
committerRichard Biener <rguenther@suse.de>2021-02-04 13:02:09 +0100
commit7002a33d1ba81e4577d965fb9daaee146b31faa8 (patch)
tree75b50e60b8279147077ef320209b7bd1ac11358f /gcc/tree-vect-loop.c
parentf0e618faeb619ec02dabbef203a5575fca44a7f7 (diff)
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tree-optimization/98855 - fix some vectorizer cost issues
This fixes us not costing vectorized bswap for SLP as well as avoiding biasing to the vectorized side when costing single-argument PHIs. Instead we assume coalescing here and cost them with zero cost for both the scalar and vectorized code. This doesn't fix the PR on its own. 2021-02-04 Richard Biener <rguenther@suse.de> PR tree-optimization/98855 * tree-vect-loop.c (vectorizable_phi): Do not cost single-argument PHIs. * tree-vect-slp.c (vect_bb_slp_scalar_cost): Likewise. * tree-vect-stmts.c (vectorizable_bswap): Also perform costing for SLP operation.
Diffstat (limited to 'gcc/tree-vect-loop.c')
-rw-r--r--gcc/tree-vect-loop.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 200ed27..f1f16e3 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -7777,8 +7777,12 @@ vectorizable_phi (vec_info *,
"incompatible vector types for invariants\n");
return false;
}
- record_stmt_cost (cost_vec, SLP_TREE_NUMBER_OF_VEC_STMTS (slp_node),
- vector_stmt, stmt_info, vectype, 0, vect_body);
+ /* For single-argument PHIs assume coalescing which means zero cost
+ for the scalar and the vector PHIs. This avoids artificially
+ favoring the vector path (but may pessimize it in some cases). */
+ if (gimple_phi_num_args (as_a <gphi *> (stmt_info->stmt)) > 1)
+ record_stmt_cost (cost_vec, SLP_TREE_NUMBER_OF_VEC_STMTS (slp_node),
+ vector_stmt, stmt_info, vectype, 0, vect_body);
STMT_VINFO_TYPE (stmt_info) = phi_info_type;
return true;
}