#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "rtl.h"
#include "regs.h"
#include "expr.h"
#include "tree-pass.h"
#include "basic-block.h"
#include "flags.h"
#include "df.h"

Include dependency graph for init-regs.c:

Functions
static void	initialize_uninitialized_regs ()
static bool	gate_initialize_regs ()
static unsigned int	rest_of_handle_initialize_regs ()
rtl_opt_pass *	make_pass_initialize_regs ()

Function Documentation

static bool gate_initialize_regs ( )

static

References initialize_uninitialized_regs().

Referenced by rest_of_handle_initialize_regs().

static void initialize_uninitialized_regs ( )

static

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see http://www.gnu.org/licenses/. Check all of the uses of pseudo variables. If any use that is MUST uninitialized, add a store of 0 immediately before it. For subregs, this makes combine happy. For full word regs, this makes other optimizations, like the register allocator and the reg-stack happy as well as papers over some problems on the arm and other processors where certain isa constraints cannot be handled by gcc. These are of the form where two operands to an insn my not be the same. The ra will only make them the same if they do not interfere, and this can only happen if one is not initialized.

There is also the unfortunate consequence that this may mask some buggy programs where people forget to initialize stack variable. Any programmer with half a brain would look at the uninitialized variable warnings.

             Only do this for the pseudos.

             Do not generate multiple moves for the same regno.
             This is common for sequences of subreg operations.
             They would be deleted during combine but there is no
             reason to churn the system.

             A use is MUST uninitialized if it reaches the top of
             the block from the inside of the block (the lr test)
             and no def for it reaches the top of the block from
             outside of the block (the ur test).

Referenced by gate_initialize_regs().

rtl_opt_pass* make_pass_initialize_regs ( )

static unsigned int rest_of_handle_initialize_regs ( )

static

References execute(), gate_initialize_regs(), OPTGROUP_NONE, RTL_PASS, TODO_df_finish, and TV_NONE.

Functions

Function Documentation