/* Basic blocks we are splitting away. */
bitmap split_bbs;
+
+ /* True when return value is computed on split part and thus it needs
+ to be returned. */
+ bool split_part_set_retval;
};
/* Best split point found. */
struct split_point best_split_point;
+static tree find_retval (basic_block return_bb);
+
/* Callback for walk_stmt_load_store_addr_ops. If T is non-ssa automatic
variable, check it if it is present in bitmap passed via DATA. */
|| (TREE_CODE (t) == RESULT_DECL)
|| (TREE_CODE (t) == PARM_DECL)))
return bitmap_bit_p ((bitmap)data, DECL_UID (t));
+
+ /* For DECL_BY_REFERENCE, the return value is actually pointer. We want to pretend
+ that the value pointed to is actual result decl. */
+ if (t && (TREE_CODE (t) == MEM_REF || INDIRECT_REF_P (t))
+ && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME
+ && TREE_CODE (SSA_NAME_VAR (TREE_OPERAND (t, 0))) == RESULT_DECL
+ && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl)))
+ return bitmap_bit_p ((bitmap)data, DECL_UID (DECL_RESULT (current_function_decl)));
return false;
}
gimple_stmt_iterator bsi;
unsigned int i;
int incomming_freq = 0;
+ tree retval;
if (dump_file && (dump_flags & TDF_DETAILS))
dump_split_point (dump_file, current);
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " Accepted!\n");
+ /* See if retval used by return bb is computed by header or split part.
+ When it is computed by split part, we need to produce return statement
+ in the split part and add code to header to pass it around.
+
+ This is bit tricky to test:
+ 1) When there is no return_bb or no return value, we always pass
+ value around.
+ 2) Invariants are always computed by caller.
+ 3) For SSA we need to look if defining statement is in header or split part
+ 4) For non-SSA we need to look where the var is computed. */
+ retval = find_retval (return_bb);
+ if (!retval)
+ current->split_part_set_retval = true;
+ else if (is_gimple_min_invariant (retval))
+ current->split_part_set_retval = false;
+ /* Special case is value returned by reference we record as if it was non-ssa
+ set to result_decl. */
+ else if (TREE_CODE (retval) == SSA_NAME
+ && TREE_CODE (SSA_NAME_VAR (retval)) == RESULT_DECL
+ && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl)))
+ current->split_part_set_retval
+ = bitmap_bit_p (non_ssa_vars, DECL_UID (SSA_NAME_VAR (retval)));
+ else if (TREE_CODE (retval) == SSA_NAME)
+ current->split_part_set_retval
+ = (!SSA_NAME_IS_DEFAULT_DEF (retval)
+ && (bitmap_bit_p (current->split_bbs,
+ gimple_bb (SSA_NAME_DEF_STMT (retval))->index)
+ || gimple_bb (SSA_NAME_DEF_STMT (retval)) == return_bb));
+ else if (TREE_CODE (retval) == PARM_DECL)
+ current->split_part_set_retval = false;
+ else if (TREE_CODE (retval) == VAR_DECL
+ || TREE_CODE (retval) == RESULT_DECL)
+ current->split_part_set_retval
+ = bitmap_bit_p (non_ssa_vars, DECL_UID (retval));
+ else
+ current->split_part_set_retval = true;
+
/* At the moment chose split point with lowest frequency and that leaves
out smallest size of header.
In future we might re-consider this heuristics. */
if ((TREE_CODE (t) == VAR_DECL && auto_var_in_fn_p (t, current_function_decl))
|| (TREE_CODE (t) == RESULT_DECL))
bitmap_set_bit ((bitmap)data, DECL_UID (t));
+
+ /* For DECL_BY_REFERENCE, the return value is actually pointer. We want to pretend
+ that the value pointed to is actual result decl. */
+ if (t && (TREE_CODE (t) == MEM_REF || INDIRECT_REF_P (t))
+ && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME
+ && TREE_CODE (SSA_NAME_VAR (TREE_OPERAND (t, 0))) == RESULT_DECL
+ && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl)))
+ return bitmap_bit_p ((bitmap)data, DECL_UID (DECL_RESULT (current_function_decl)));
return false;
}
FOR_EACH_EDGE (e, ei, bb->succs)
if (e->dest == return_bb)
{
- bool found_phi = false;
for (bsi = gsi_start_phis (return_bb); !gsi_end_p (bsi); gsi_next (&bsi))
{
gimple stmt = gsi_stmt (bsi);
continue;
if (!is_gimple_reg (gimple_phi_result (stmt)))
continue;
- found_phi = true;
if (TREE_CODE (op) == SSA_NAME)
bitmap_set_bit (used_ssa_names, SSA_NAME_VERSION (op));
else
can_split &= !mark_nonssa_use (stmt, op, non_ssa_vars);
}
- if (!gsi_end_p (gsi_last_bb (return_bb)))
- {
- ssa_op_iter iter;
- gimple stmt = gsi_stmt (gsi_last_bb (return_bb));
- tree op;
- if (!found_phi)
- FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
- bitmap_set_bit (used_ssa_names, SSA_NAME_VERSION (op));
- can_split &= !walk_stmt_load_store_addr_ops (stmt, non_ssa_vars,
- mark_nonssa_use,
- mark_nonssa_use,
- mark_nonssa_use);
- }
}
return can_split;
}
if (e)
split_part_return_p = true;
- /* If we return, we will need the return block. */
- if (return_bb != EXIT_BLOCK_PTR && split_part_return_p)
+ /* Add return block to what will become the split function.
+ We do not return; no return block is needed. */
+ if (!split_part_return_p)
+ ;
+ /* We have no return block, so nothing is needed. */
+ else if (return_bb == EXIT_BLOCK_PTR)
+ ;
+ /* When we do not want to return value, we need to construct
+ new return block with empty return statement.
+ FIXME: Once we are able to change return type, we should change function
+ to return void instead of just outputting function with undefined return
+ value. For structures this affects quality of codegen. */
+ else if (!split_point->split_part_set_retval
+ && find_retval (return_bb))
+ {
+ bool redirected = true;
+ basic_block new_return_bb = create_basic_block (NULL, 0, return_bb);
+ gimple_stmt_iterator gsi = gsi_start_bb (new_return_bb);
+ gsi_insert_after (&gsi, gimple_build_return (NULL), GSI_NEW_STMT);
+ while (redirected)
+ {
+ redirected = false;
+ FOR_EACH_EDGE (e, ei, return_bb->preds)
+ if (bitmap_bit_p (split_point->split_bbs, e->src->index))
+ {
+ new_return_bb->count += e->count;
+ new_return_bb->frequency += EDGE_FREQUENCY (e);
+ redirect_edge_and_branch (e, new_return_bb);
+ redirected = true;
+ break;
+ }
+ }
+ e = make_edge (new_return_bb, EXIT_BLOCK_PTR, 0);
+ e->probability = REG_BR_PROB_BASE;
+ e->count = new_return_bb->count;
+ bitmap_set_bit (split_point->split_bbs, new_return_bb->index);
+ /* We change CFG in a way tree-inline is not able to compensate on while
+ updating PHIs. There are only virtuals in return_bb, so recompute
+ them. */
+ for (gsi = gsi_start_phis (return_bb); !gsi_end_p (gsi);)
+ {
+ gimple stmt = gsi_stmt (gsi);
+ gcc_assert (!is_gimple_reg (gimple_phi_result (stmt)));
+ mark_sym_for_renaming (SSA_NAME_VAR (PHI_RESULT (stmt)));
+ gsi_remove (&gsi, false);
+ }
+ }
+ /* When we pass aorund the value, use existing return block. */
+ else
bitmap_set_bit (split_point->split_bbs, return_bb->index);
/* Now create the actual clone. */
{
real_retval = retval = find_retval (return_bb);
- /* See if return value is computed by split part;
- function might just return its argument, invariant or undefined
- value. In this case we don't need to do any updating. */
- if (real_retval
- && !is_gimple_min_invariant (retval)
- && (TREE_CODE (retval) != SSA_NAME
- || (!SSA_NAME_IS_DEFAULT_DEF (retval)
- || DECL_BY_REFERENCE
- (DECL_RESULT (current_function_decl)))))
+ if (real_retval && split_point->split_part_set_retval)
{
gimple_stmt_iterator psi;
else
{
gimple ret;
- if (!VOID_TYPE_P (TREE_TYPE (TREE_TYPE (current_function_decl))))
+ if (split_point->split_part_set_retval
+ && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (current_function_decl))))
{
retval = DECL_RESULT (current_function_decl);