On 6/24/20 9:43 AM, Richard Biener wrote:
Hmm, can you instead use simple_dce_from_worklist and simply
record all SSA_NAMEs you end up "forwarding" as possibly dead
in a bitmap? At least that hashmap traversal looks dangerous
with respect to address-space randomization and gsi_remove
inserting debug stmts and thus eventually allocating debug decls.
Sure, done in the updated patch.
Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
Ready to be installed?
Thanks,
Martin
>From ad8d574ea5bcd0f123e0c890825babbd3bbc5eef Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Wed, 24 Jun 2020 08:08:00 +0200
Subject: [PATCH] VEC_COND_EXPR: clean up first argument
gcc/ChangeLog:
PR tree-optimization/95745
PR middle-end/95830
* gimple-isel.cc (gimple_expand_vec_cond_exprs): Delete dead
SSA_NAMEs used as the first argument of a VEC_COND_EXPR. Always
return 0.
* tree-vect-generic.c (expand_vector_condition): Remove dead
SSA_NAMEs used as the first argument of a VEC_COND_EXPR.
---
gcc/gimple-isel.cc | 14 ++++++++++++--
gcc/tree-vect-generic.c | 23 +++++++++++++++++------
2 files changed, 29 insertions(+), 8 deletions(-)
diff --git a/gcc/gimple-isel.cc b/gcc/gimple-isel.cc
index 97f92080503..f54c56eb71d 100644
--- a/gcc/gimple-isel.cc
+++ b/gcc/gimple-isel.cc
@@ -33,6 +33,8 @@ along with GCC; see the file COPYING3. If not see
#include "gimplify-me.h"
#include "gimplify.h"
#include "tree-cfg.h"
+#include "bitmap.h"
+#include "tree-ssa-dce.h"
/* Expand all VEC_COND_EXPR gimple assignments into calls to internal
function based on type of selected expansion. */
@@ -178,8 +180,8 @@ gimple_expand_vec_cond_exprs (void)
{
gimple_stmt_iterator gsi;
basic_block bb;
- bool cfg_changed = false;
hash_map<tree, unsigned int> vec_cond_ssa_name_uses;
+ bitmap dce_ssa_names = BITMAP_ALLOC (NULL);
FOR_EACH_BB_FN (bb, cfun)
{
@@ -196,7 +198,15 @@ gimple_expand_vec_cond_exprs (void)
}
}
- return cfg_changed ? TODO_cleanup_cfg : 0;
+ for (hash_map<tree, unsigned int>::iterator it = vec_cond_ssa_name_uses.begin ();
+ it != vec_cond_ssa_name_uses.end (); ++it)
+ if (num_imm_uses ((*it).first) == 0)
+ bitmap_set_bit (dce_ssa_names, SSA_NAME_VERSION ((*it).first));
+
+ simple_dce_from_worklist (dce_ssa_names);
+ BITMAP_FREE (dce_ssa_names);
+
+ return 0;
}
namespace {
diff --git a/gcc/tree-vect-generic.c b/gcc/tree-vect-generic.c
index 83d399a7898..fafe6bf2d16 100644
--- a/gcc/tree-vect-generic.c
+++ b/gcc/tree-vect-generic.c
@@ -40,10 +40,11 @@ along with GCC; see the file COPYING3. If not see
#include "tree-vector-builder.h"
#include "vec-perm-indices.h"
#include "insn-config.h"
+#include "tree-ssa-dce.h"
#include "recog.h" /* FIXME: for insn_data */
-static void expand_vector_operations_1 (gimple_stmt_iterator *);
+static void expand_vector_operations_1 (gimple_stmt_iterator *, bitmap *);
/* Return the number of elements in a vector type TYPE that we have
already decided needs to be expanded piecewise. We don't support
@@ -932,7 +933,7 @@ expand_vector_divmod (gimple_stmt_iterator *gsi, tree type, tree op0,
/* Expand a vector condition to scalars, by using many conditions
on the vector's elements. */
static void
-expand_vector_condition (gimple_stmt_iterator *gsi)
+expand_vector_condition (gimple_stmt_iterator *gsi, bitmap *dce_ssa_names)
{
gassign *stmt = as_a <gassign *> (gsi_stmt (*gsi));
tree type = gimple_expr_type (stmt);
@@ -954,10 +955,11 @@ expand_vector_condition (gimple_stmt_iterator *gsi)
tree comp_index = index;
location_t loc = gimple_location (gsi_stmt (*gsi));
tree_code code = TREE_CODE (a);
+ gassign *assign = NULL;
if (code == SSA_NAME)
{
- gassign *assign = dyn_cast<gassign *> (SSA_NAME_DEF_STMT (a));
+ assign = dyn_cast<gassign *> (SSA_NAME_DEF_STMT (a));
if (assign != NULL
&& TREE_CODE_CLASS (gimple_assign_rhs_code (assign)) == tcc_comparison)
{
@@ -1064,6 +1066,10 @@ expand_vector_condition (gimple_stmt_iterator *gsi)
constr = build_constructor (type, v);
gimple_assign_set_rhs_from_tree (gsi, constr);
update_stmt (gsi_stmt (*gsi));
+
+ if (a_is_comparison && num_imm_uses (gimple_assign_lhs (assign)) == 0)
+ bitmap_set_bit (*dce_ssa_names,
+ SSA_NAME_VERSION (gimple_assign_lhs (assign)));
}
static tree
@@ -1956,7 +1962,7 @@ expand_vector_conversion (gimple_stmt_iterator *gsi)
/* Process one statement. If we identify a vector operation, expand it. */
static void
-expand_vector_operations_1 (gimple_stmt_iterator *gsi)
+expand_vector_operations_1 (gimple_stmt_iterator *gsi, bitmap *dce_ssa_names)
{
tree lhs, rhs1, rhs2 = NULL, type, compute_type = NULL_TREE;
enum tree_code code;
@@ -1985,7 +1991,7 @@ expand_vector_operations_1 (gimple_stmt_iterator *gsi)
if (code == VEC_COND_EXPR)
{
- expand_vector_condition (gsi);
+ expand_vector_condition (gsi, dce_ssa_names);
return;
}
@@ -2233,11 +2239,13 @@ expand_vector_operations (void)
basic_block bb;
bool cfg_changed = false;
+ bitmap dce_ssa_names = BITMAP_ALLOC (NULL);
+
FOR_EACH_BB_FN (bb, cfun)
{
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
- expand_vector_operations_1 (&gsi);
+ expand_vector_operations_1 (&gsi, &dce_ssa_names);
/* ??? If we do not cleanup EH then we will ICE in
verification. But in reality we have created wrong-code
as we did not properly transition EH info and edges to
@@ -2248,6 +2256,9 @@ expand_vector_operations (void)
}
}
+ simple_dce_from_worklist (dce_ssa_names);
+ BITMAP_FREE (dce_ssa_names);
+
return cfg_changed ? TODO_cleanup_cfg : 0;
}
--
2.27.0
