===================================================================
@@ -244,7 +244,7 @@ select_best_block (basic_block early_bb,
static bool
statement_sink_location (gimple *stmt, basic_block frombb,
- gimple_stmt_iterator *togsi)
+ gimple_stmt_iterator *togsi, bool *zero_uses_p)
{
gimple *use;
use_operand_p one_use = NULL_USE_OPERAND_P;
@@ -254,6 +254,8 @@ statement_sink_location (gimple *stmt, b
ssa_op_iter iter;
imm_use_iterator imm_iter;
+ *zero_uses_p = false;
+
/* We only can sink assignments. */
if (!is_gimple_assign (stmt))
return false;
@@ -263,10 +265,6 @@ statement_sink_location (gimple *stmt, b
if (def_p == NULL_DEF_OPERAND_P)
return false;
- /* Return if there are no immediate uses of this stmt. */
- if (has_zero_uses (DEF_FROM_PTR (def_p)))
- return false;
-
/* There are a few classes of things we can't or don't move, some because we
don't have code to handle it, some because it's not profitable and some
because it's not legal.
@@ -292,11 +290,17 @@ statement_sink_location (gimple *stmt, b
*/
if (stmt_ends_bb_p (stmt)
|| gimple_has_side_effects (stmt)
- || gimple_has_volatile_ops (stmt)
|| (cfun->has_local_explicit_reg_vars
&& TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt))) == BLKmode))
return false;
+ /* Return if there are no immediate uses of this stmt. */
+ if (has_zero_uses (DEF_FROM_PTR (def_p)))
+ {
+ *zero_uses_p = true;
+ return false;
+ }
+
if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (DEF_FROM_PTR (def_p)))
return false;
@@ -483,12 +487,23 @@ sink_code_in_bb (basic_block bb)
{
gimple *stmt = gsi_stmt (gsi);
gimple_stmt_iterator togsi;
+ bool zero_uses_p;
- if (!statement_sink_location (stmt, bb, &togsi))
+ if (!statement_sink_location (stmt, bb, &togsi, &zero_uses_p))
{
+ gimple_stmt_iterator saved = gsi;
if (!gsi_end_p (gsi))
gsi_prev (&gsi);
- last = false;
+ /* If we face a dead stmt remove it as it possibly blocks
+ sinking of uses. */
+ if (zero_uses_p
+ && ! gimple_vdef (stmt))
+ {
+ gsi_remove (&saved, true);
+ release_defs (stmt);
+ }
+ else
+ last = false;
continue;
}
if (dump_file)