/* Function splitting pass
- Copyright (C) 2010, 2011
+ Copyright (C) 2010, 2011, 2012
Free Software Foundation, Inc.
Contributed by Jan Hubicka <jh@suse.cz>
struct split_point best_split_point;
+/* Set of basic blocks that are not allowed to dominate a split point. */
+
+static bitmap forbidden_dominators;
+
static tree find_retval (basic_block return_bb);
/* Callback for walk_stmt_load_store_addr_ops. If T is non-SSA automatic
return ok;
}
+/* If STMT is a call, check the callee against a list of forbidden
+ predicate functions. If a match is found, look for uses of the
+ call result in condition statements that compare against zero.
+ For each such use, find the block targeted by the condition
+ statement for the nonzero result, and set the bit for this block
+ in the forbidden dominators bitmap. The purpose of this is to avoid
+ selecting a split point where we are likely to lose the chance
+ to optimize away an unused function call. */
+
+static void
+check_forbidden_calls (gimple stmt)
+{
+ imm_use_iterator use_iter;
+ use_operand_p use_p;
+ tree lhs;
+
+ /* At the moment, __builtin_constant_p is the only forbidden
+ predicate function call (see PR49642). */
+ if (!gimple_call_builtin_p (stmt, BUILT_IN_CONSTANT_P))
+ return;
+
+ lhs = gimple_call_lhs (stmt);
+
+ if (!lhs || TREE_CODE (lhs) != SSA_NAME)
+ return;
+
+ FOR_EACH_IMM_USE_FAST (use_p, use_iter, lhs)
+ {
+ tree op1;
+ basic_block use_bb, forbidden_bb;
+ enum tree_code code;
+ edge true_edge, false_edge;
+ gimple use_stmt = USE_STMT (use_p);
+
+ if (gimple_code (use_stmt) != GIMPLE_COND)
+ continue;
+
+ /* Assuming canonical form for GIMPLE_COND here, with constant
+ in second position. */
+ op1 = gimple_cond_rhs (use_stmt);
+ code = gimple_cond_code (use_stmt);
+ use_bb = gimple_bb (use_stmt);
+
+ extract_true_false_edges_from_block (use_bb, &true_edge, &false_edge);
+
+ /* We're only interested in comparisons that distinguish
+ unambiguously from zero. */
+ if (!integer_zerop (op1) || code == LE_EXPR || code == GE_EXPR)
+ continue;
+
+ if (code == EQ_EXPR)
+ forbidden_bb = false_edge->dest;
+ else
+ forbidden_bb = true_edge->dest;
+
+ bitmap_set_bit (forbidden_dominators, forbidden_bb->index);
+ }
+}
+
+/* If BB is dominated by any block in the forbidden dominators set,
+ return TRUE; else FALSE. */
+
+static bool
+dominated_by_forbidden (basic_block bb)
+{
+ unsigned dom_bb;
+ bitmap_iterator bi;
+
+ EXECUTE_IF_SET_IN_BITMAP (forbidden_dominators, 1, dom_bb, bi)
+ {
+ if (dominated_by_p (CDI_DOMINATORS, bb, BASIC_BLOCK (dom_bb)))
+ return true;
+ }
+
+ return false;
+}
+
/* We found an split_point CURRENT. NON_SSA_VARS is bitmap of all non ssa
variables used and RETURN_BB is return basic block.
See if we can split function here. */
" Refused: split part has non-ssa uses\n");
return;
}
+
+ /* If the split point is dominated by a forbidden block, reject
+ the split. */
+ if (!bitmap_empty_p (forbidden_dominators)
+ && dominated_by_forbidden (current->entry_bb))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file,
+ " Refused: split point dominated by forbidden block\n");
+ return;
+ }
+
/* 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.
for (bsi = gsi_last_bb (e->src); !gsi_end_p (bsi); gsi_prev (&bsi))
{
gimple stmt = gsi_stmt (bsi);
- if (gimple_code (stmt) == GIMPLE_LABEL || is_gimple_debug (stmt))
+ if (gimple_code (stmt) == GIMPLE_LABEL
+ || is_gimple_debug (stmt)
+ || gimple_clobber_p (stmt))
;
else if (gimple_code (stmt) == GIMPLE_ASSIGN
&& found_return
for (bsi = gsi_start_bb (return_bb); !gsi_end_p (bsi); gsi_next (&bsi))
if (gimple_code (gsi_stmt (bsi)) == GIMPLE_RETURN)
return gimple_return_retval (gsi_stmt (bsi));
- else if (gimple_code (gsi_stmt (bsi)) == GIMPLE_ASSIGN)
+ else if (gimple_code (gsi_stmt (bsi)) == GIMPLE_ASSIGN
+ && !gimple_clobber_p (gsi_stmt (bsi)))
return gimple_assign_rhs1 (gsi_stmt (bsi));
return NULL;
}
if (is_gimple_debug (stmt))
continue;
+ if (gimple_clobber_p (stmt))
+ continue;
+
/* FIXME: We can split regions containing EH. We can not however
split RESX, EH_DISPATCH and EH_POINTER referring to same region
into different partitions. This would require tracking of
split_function (struct split_point *split_point)
{
VEC (tree, heap) *args_to_pass = NULL;
- bitmap args_to_skip = BITMAP_ALLOC (NULL);
+ bitmap args_to_skip;
tree parm;
int num = 0;
- struct cgraph_node *node;
+ struct cgraph_node *node, *cur_node = cgraph_get_node (current_function_decl);
basic_block return_bb = find_return_bb ();
basic_block call_bb;
gimple_stmt_iterator gsi;
tree retval = NULL, real_retval = NULL;
bool split_part_return_p = false;
gimple last_stmt = NULL;
- bool conv_needed = false;
unsigned int i;
tree arg;
dump_split_point (dump_file, split_point);
}
+ if (cur_node->local.can_change_signature)
+ args_to_skip = BITMAP_ALLOC (NULL);
+ else
+ args_to_skip = NULL;
+
/* Collect the parameters of new function and args_to_skip bitmap. */
for (parm = DECL_ARGUMENTS (current_function_decl);
parm; parm = DECL_CHAIN (parm), num++)
- if (!is_gimple_reg (parm)
- || !gimple_default_def (cfun, parm)
- || !bitmap_bit_p (split_point->ssa_names_to_pass,
- SSA_NAME_VERSION (gimple_default_def (cfun, parm))))
+ if (args_to_skip
+ && (!is_gimple_reg (parm)
+ || !gimple_default_def (cfun, parm)
+ || !bitmap_bit_p (split_point->ssa_names_to_pass,
+ SSA_NAME_VERSION (gimple_default_def (cfun,
+ parm)))))
bitmap_set_bit (args_to_skip, num);
else
{
- arg = gimple_default_def (cfun, parm);
- if (TYPE_MAIN_VARIANT (DECL_ARG_TYPE (parm))
- != TYPE_MAIN_VARIANT (TREE_TYPE (arg)))
+ /* This parm might not have been used up to now, but is going to be
+ used, hence register it. */
+ add_referenced_var (parm);
+ if (is_gimple_reg (parm))
{
- conv_needed = true;
- arg = fold_convert (DECL_ARG_TYPE (parm), arg);
+ arg = gimple_default_def (cfun, parm);
+ if (!arg)
+ {
+ arg = make_ssa_name (parm, gimple_build_nop ());
+ set_default_def (parm, arg);
+ }
}
+ else
+ arg = parm;
+
+ if (!useless_type_conversion_p (DECL_ARG_TYPE (parm), TREE_TYPE (arg)))
+ arg = fold_convert (DECL_ARG_TYPE (parm), arg);
VEC_safe_push (tree, heap, args_to_pass, arg);
}
/* Now create the actual clone. */
rebuild_cgraph_edges ();
- node = cgraph_function_versioning (cgraph_get_node (current_function_decl),
- NULL, NULL,
- args_to_skip,
+ node = cgraph_function_versioning (cur_node, NULL, NULL, args_to_skip,
+ !split_part_return_p,
split_point->split_bbs,
split_point->entry_bb, "part");
/* For usual cloning it is enough to clear builtin only when signature
DECL_BUILT_IN_CLASS (node->decl) = NOT_BUILT_IN;
DECL_FUNCTION_CODE (node->decl) = (enum built_in_function) 0;
}
- cgraph_node_remove_callees (cgraph_get_node (current_function_decl));
+ cgraph_node_remove_callees (cur_node);
if (!split_part_return_p)
TREE_THIS_VOLATILE (node->decl) = 1;
if (dump_file)
/* Produce the call statement. */
gsi = gsi_last_bb (call_bb);
- if (conv_needed)
- FOR_EACH_VEC_ELT (tree, args_to_pass, i, arg)
- if (!is_gimple_val (arg))
- {
- arg = force_gimple_operand_gsi (&gsi, arg, true, NULL_TREE,
- false, GSI_NEW_STMT);
- VEC_replace (tree, args_to_pass, i, arg);
- }
+ FOR_EACH_VEC_ELT (tree, args_to_pass, i, arg)
+ if (!is_gimple_val (arg))
+ {
+ arg = force_gimple_operand_gsi (&gsi, arg, true, NULL_TREE,
+ false, GSI_CONTINUE_LINKING);
+ VEC_replace (tree, args_to_pass, i, arg);
+ }
call = gimple_build_call_vec (node->decl, args_to_pass);
gimple_set_block (call, DECL_INITIAL (current_function_decl));
gimple_return_set_retval (gsi_stmt (bsi), retval);
break;
}
- else if (gimple_code (gsi_stmt (bsi)) == GIMPLE_ASSIGN)
+ else if (gimple_code (gsi_stmt (bsi)) == GIMPLE_ASSIGN
+ && !gimple_clobber_p (gsi_stmt (bsi)))
{
gimple_assign_set_rhs1 (gsi_stmt (bsi), retval);
break;
int todo = 0;
struct cgraph_node *node = cgraph_get_node (current_function_decl);
- if (flags_from_decl_or_type (current_function_decl) & ECF_NORETURN)
+ if (flags_from_decl_or_type (current_function_decl)
+ & (ECF_NORETURN|ECF_MALLOC))
{
if (dump_file)
- fprintf (dump_file, "Not splitting: noreturn function.\n");
+ fprintf (dump_file, "Not splitting: noreturn/malloc function.\n");
return 0;
}
if (MAIN_NAME_P (DECL_NAME (current_function_decl)))
return 0;
}
+ /* Initialize bitmap to track forbidden calls. */
+ forbidden_dominators = BITMAP_ALLOC (NULL);
+ calculate_dominance_info (CDI_DOMINATORS);
+
/* Compute local info about basic blocks and determine function size/time. */
VEC_safe_grow_cleared (bb_info, heap, bb_info_vec, last_basic_block + 1);
memset (&best_split_point, 0, sizeof (best_split_point));
this_time = estimate_num_insns (stmt, &eni_time_weights) * freq;
size += this_size;
time += this_time;
+ check_forbidden_calls (stmt);
if (dump_file && (dump_flags & TDF_DETAILS))
{
BITMAP_FREE (best_split_point.split_bbs);
todo = TODO_update_ssa | TODO_cleanup_cfg;
}
+ BITMAP_FREE (forbidden_dominators);
VEC_free (bb_info, heap, bb_info_vec);
bb_info_vec = NULL;
return todo;
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- 0 /* todo_flags_finish */
+ TODO_verify_all /* todo_flags_finish */
}
};
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- 0 /* todo_flags_finish */
+ TODO_verify_all /* todo_flags_finish */
}
};
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