* [PATCH] Improve DCE of dead parts of a permute chain
@ 2023-12-20 13:43 Richard Biener
0 siblings, 0 replies; only message in thread
From: Richard Biener @ 2023-12-20 13:43 UTC (permalink / raw)
To: gcc-patches
gcc.dg/vect/bb-slp-pr78205.c is reported to have regressed with
the PR113073 change and in the end it's due to the DCE performed
by vect_transform_slp_perm_load_1 being imperfect. The following
enhances it to also cover the CTOR and VIEW_CONVERT operations that
might be involved.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
* tree-vect-slp.cc (vect_transform_slp_perm_load_1): Also handle
CTOR and VIEW_CONVERT up to the load when performing chain DCE.
---
gcc/tree-vect-slp.cc | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index a82fca45161..1a357cb7549 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -8634,10 +8634,21 @@ vect_transform_slp_perm_load_1 (vec_info *vinfo, slp_tree node,
for (unsigned i = 0; i < dr_chain.length (); ++i)
if (!bitmap_bit_p (used_defs, i))
{
- gimple *stmt = SSA_NAME_DEF_STMT (dr_chain[i]);
- gimple_stmt_iterator rgsi = gsi_for_stmt (stmt);
- gsi_remove (&rgsi, true);
- release_defs (stmt);
+ tree def = dr_chain[i];
+ do
+ {
+ gimple *stmt = SSA_NAME_DEF_STMT (def);
+ if (is_gimple_assign (stmt)
+ && (gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR
+ || gimple_assign_rhs_code (stmt) == CONSTRUCTOR))
+ def = single_ssa_tree_operand (stmt, SSA_OP_USE);
+ else
+ def = NULL;
+ gimple_stmt_iterator rgsi = gsi_for_stmt (stmt);
+ gsi_remove (&rgsi, true);
+ release_defs (stmt);
+ }
+ while (def);
}
return true;
--
2.35.3
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