Hi,
This patch adds a bounds lifetime reduction into checker optimization.
Thanks,
Ilya
--
2014-10-08 Ilya Enkovich <ilya.enkov...@intel.com>
* tree-chkp.c (chkp_reduce_bounds_lifetime): New.
(chkp_opt_execute): Run bounds lifetime reduction
algorithm.
diff --git a/gcc/tree-chkp.c b/gcc/tree-chkp.c
index 37ab729..60e4c11 100644
--- a/gcc/tree-chkp.c
+++ b/gcc/tree-chkp.c
@@ -5420,6 +5420,155 @@ chkp_optimize_string_function_calls (void)
}
}
+/* Intrumentation pass inserts most of bounds creation code
+ in the header of the function. We want to move bounds
+ creation closer to bounds usage to reduce bounds lifetime.
+ We also try to avoid bounds creation code on paths where
+ bounds are not used. */
+void
+chkp_reduce_bounds_lifetime (void)
+{
+ basic_block bb = FALLTHRU_EDGE (ENTRY_BLOCK_PTR_FOR_FN (cfun))->dest;
+ gimple_stmt_iterator i;
+
+ for (i = gsi_start_bb (bb); !gsi_end_p (i); )
+ {
+ gimple dom_use, use_stmt, stmt = gsi_stmt (i);
+ basic_block dom_bb;
+ ssa_op_iter iter;
+ imm_use_iterator use_iter;
+ use_operand_p use_p;
+ tree op;
+ bool want_move = false;
+ bool deps = false;
+
+ if (gimple_code (stmt) == GIMPLE_CALL
+ && gimple_call_fndecl (stmt) == chkp_bndmk_fndecl)
+ want_move = true;
+
+ if (gimple_code (stmt) == GIMPLE_ASSIGN
+ && POINTER_BOUNDS_P (gimple_assign_lhs (stmt))
+ && gimple_assign_rhs_code (stmt) == VAR_DECL)
+ want_move = true;
+
+ if (!want_move)
+ {
+ gsi_next (&i);
+ continue;
+ }
+
+ /* Check we do not increase other values lifetime. */
+ FOR_EACH_PHI_OR_STMT_USE (use_p, stmt, iter, SSA_OP_USE)
+ {
+ op = USE_FROM_PTR (use_p);
+
+ if (TREE_CODE (op) == SSA_NAME
+ && gimple_code (SSA_NAME_DEF_STMT (op)) != GIMPLE_NOP)
+ deps = true;
+ }
+
+ if (deps)
+ {
+ gsi_next (&i);
+ continue;
+ }
+
+ /* Check all usages of bounds. */
+ if (gimple_code (stmt) == GIMPLE_CALL)
+ op = gimple_call_lhs (stmt);
+ else
+ {
+ gcc_assert (gimple_code (stmt) == GIMPLE_ASSIGN);
+ op = gimple_assign_lhs (stmt);
+ }
+
+ dom_use = NULL;
+ dom_bb = NULL;
+
+ FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, op)
+ {
+ if (dom_bb &&
+ dominated_by_p (CDI_DOMINATORS,
+ dom_bb, gimple_bb (use_stmt)))
+ {
+ dom_use = use_stmt;
+ dom_bb = NULL;
+ }
+ else if (dom_bb)
+ dom_bb = nearest_common_dominator (CDI_DOMINATORS, dom_bb,
+ gimple_bb (use_stmt));
+ else if (!dom_use)
+ dom_use = use_stmt;
+ else if (stmt_dominates_stmt_p (use_stmt, dom_use))
+ dom_use = use_stmt;
+ else if (!stmt_dominates_stmt_p (dom_use, use_stmt)
+ /* If dom_use and use_stmt are PHI nodes in one BB
+ then it is OK to keep any of them as dom_use.
+ stmt_dominates_stmt_p returns 0 for such
+ combination, so check it here manually. */
+ && (gimple_code (dom_use) != GIMPLE_PHI
+ || gimple_code (use_stmt) != GIMPLE_PHI
+ || gimple_bb (use_stmt) != gimple_bb (dom_use))
+ )
+ {
+ dom_bb = nearest_common_dominator (CDI_DOMINATORS,
+ gimple_bb (use_stmt),
+ gimple_bb (dom_use));
+ dom_use = NULL;
+ }
+ }
+
+ /* In case there is a single use, just move bounds
+ creation to the use. */
+ if (dom_use || dom_bb)
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Moving creation of ");
+ print_generic_expr (dump_file, op, 0);
+ fprintf (dump_file, " down to its use.\n");
+ }
+
+ if (dom_use && gimple_code (dom_use) == GIMPLE_PHI)
+ {
+ dom_bb = get_immediate_dominator (CDI_DOMINATORS,
+ gimple_bb (dom_use));
+ dom_use = NULL;
+ }
+
+ if (dom_bb == bb
+ || (dom_use && gimple_bb (dom_use) == bb))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Cannot move statement bacause there is
no "
+ "suitable dominator block other than entry
block.\n");
+
+ gsi_next (&i);
+ }
+ else
+ {
+ if (dom_bb)
+ {
+ gimple_stmt_iterator last = gsi_last_bb (dom_bb);
+ if (!gsi_end_p (last) && stmt_ends_bb_p (gsi_stmt (last)))
+ gsi_move_before (&i, &last);
+ else
+ gsi_move_after (&i, &last);
+ }
+ else
+ {
+ gimple_stmt_iterator gsi = gsi_for_stmt (dom_use);
+ gsi_move_before (&i, &gsi);
+ }
+
+ update_stmt (stmt);
+ }
+ }
+ else
+ gsi_next (&i);
+ }
+}
+
/* Initilize checker optimization pass. */
void
chkp_opt_init (void)
@@ -5464,6 +5613,8 @@ chkp_opt_execute (void)
chkp_remove_redundant_checks ();
+ chkp_reduce_bounds_lifetime ();
+
chkp_release_check_info ();
chkp_opt_fini ();
