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optimizer.c
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optimizer.c
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/*
* Copyright (C) 2002-2012, Parrot Foundation.
*/
/*
=head1 NAME
compilers/imcc/optimizer.c
=head1 DESCRIPTION
Optimization occurs in three stages:
1) pre_optimizer -- runs before control flow graph (CFG) is built
2) optimizer -- runs after CFG is built, but before register allocation
3) post_optimizer -- runs after register allocation
pre_optimizer
-------------
During pre-optimization we perform optimizations which don't require
full knowledge of the control flow graph and the life ranges of each
variable. This phase is handled by two functions: pre_optimize() and
cfg_optimize().
pre_optimize() runs before the construction of the CFG begins. It calls
strength_reduce() to perform simple strength reduction, and if_branch()
to rewrite certain if/branch/label constructs (for details, see
if_branch() below).
[pre_optimize() may also be called later, during the main optimization
phase, but this is not guaranteed.]
cfg_optimize() runs during the construction of the CFG. It calls
branch_branch() to perform jump optimization (i.e. branches to
branch statements or jumps to jumps are converted into single
branches/jumps to the final destination), unused_label() to remove
unused labels and dead_code_remove() to remove unreachable code
(e.g. basic blocks which are never entered or instructions after
and unconditional branch which are never branched to).
cfg_optimize may be called multiple times during the construction of the
CFG depending on whether or not it finds anything to optimize.
subst_constants ... rewrite e.g. add_i_ic_ic
optimizer
---------
runs with CFG and life info
used_once ... deletes assignments, when LHS is unused
constant_propagation
post_optimizer: currently pcc_optimize in pcc.c
---------------
runs after register allocation
e.g. eliminate new Px .PerlUndef because Px where different before
=head2 Functions
=over 4
=cut
*/
#include <string.h>
#include "imc.h"
#include "pbc.h"
#include "optimizer.h"
#include "pmc/pmc_callcontext.h"
#include "parrot/oplib/core_ops.h"
/* HEADERIZER HFILE: compilers/imcc/optimizer.h */
/* HEADERIZER BEGIN: static */
/* Don't modify between HEADERIZER BEGIN / HEADERIZER END. Your changes will be lost. */
static int branch_branch(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit);
static int branch_cond_loop(
ARGMOD(imc_info_t *imcc),
ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit);
PARROT_WARN_UNUSED_RESULT
static int branch_cond_loop_swap(
ARGMOD(imc_info_t *imcc),
ARGMOD(IMC_Unit *unit),
ARGMOD(Instruction *branch),
ARGMOD(Instruction *start),
ARGMOD(Instruction *cond))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
__attribute__nonnull__(3)
__attribute__nonnull__(4)
__attribute__nonnull__(5)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit)
FUNC_MODIFIES(*branch)
FUNC_MODIFIES(*start)
FUNC_MODIFIES(*cond);
PARROT_WARN_UNUSED_RESULT
static int branch_reorg(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit);
static int constant_propagation(
ARGMOD(imc_info_t *imcc),
ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit);
static int dead_code_remove(
ARGMOD(imc_info_t *imcc),
ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit);
PARROT_WARN_UNUSED_RESULT
static int eval_ins(
ARGMOD(imc_info_t *imcc),
ARGIN(const char *op),
size_t ops,
ARGIN(SymReg **r))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
__attribute__nonnull__(4)
FUNC_MODIFIES(*imcc);
static int if_branch(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit);
static int strength_reduce(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit);
PARROT_WARN_UNUSED_RESULT
static int unused_label(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit);
static int used_once(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
__attribute__nonnull__(1)
__attribute__nonnull__(2)
FUNC_MODIFIES(*imcc)
FUNC_MODIFIES(*unit);
#define ASSERT_ARGS_branch_branch __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_branch_cond_loop __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_branch_cond_loop_swap __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit) \
, PARROT_ASSERT_ARG(branch) \
, PARROT_ASSERT_ARG(start) \
, PARROT_ASSERT_ARG(cond))
#define ASSERT_ARGS_branch_reorg __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_constant_propagation __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_dead_code_remove __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_eval_ins __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(op) \
, PARROT_ASSERT_ARG(r))
#define ASSERT_ARGS_if_branch __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_strength_reduce __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_unused_label __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit))
#define ASSERT_ARGS_used_once __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
PARROT_ASSERT_ARG(imcc) \
, PARROT_ASSERT_ARG(unit))
/* Don't modify between HEADERIZER BEGIN / HEADERIZER END. Your changes will be lost. */
/* HEADERIZER END: static */
/*
=item C<int pre_optimize(imc_info_t *imcc, IMC_Unit *unit)>
Handles optimizations occuring before the construction of the CFG.
=cut
*/
int
pre_optimize(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
{
ASSERT_ARGS(pre_optimize)
int changed = 0;
if (imcc->optimizer_level & OPT_PRE) {
IMCC_info(imcc, 2, "pre_optimize\n");
changed += strength_reduce(imcc, unit);
if (!imcc->dont_optimize)
changed += if_branch(imcc, unit);
}
return changed;
}
/*
=item C<int cfg_optimize(imc_info_t *imcc, IMC_Unit *unit)>
Handles optimizations occuring during the construction of the CFG.
Returns TRUE if any optimization was performed. Otherwise, returns
FALSE.
=cut
*/
PARROT_WARN_UNUSED_RESULT
int
cfg_optimize(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
{
ASSERT_ARGS(cfg_optimize)
if (imcc->dont_optimize)
return 0;
if (imcc->optimizer_level & OPT_PRE) {
IMCC_info(imcc, 2, "cfg_optimize\n");
if (branch_branch(imcc, unit))
return 1;
if (branch_cond_loop(imcc, unit))
return 1;
if (branch_reorg(imcc, unit))
return 1;
if (unused_label(imcc, unit))
return 1;
if (dead_code_remove(imcc, unit))
return 1;
}
return 0;
}
/*
=item C<int optimize(imc_info_t *imcc, IMC_Unit *unit)>
Runs after the CFG is built and handles constant propagation.
used_once ... deletes assignments, when LHS is unused
=cut
*/
int
optimize(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
{
ASSERT_ARGS(optimize)
int any = 0;
if (imcc->optimizer_level & OPT_CFG) {
IMCC_info(imcc, 2, "optimize\n");
any = constant_propagation(imcc, unit);
if (used_once(imcc, unit))
return 1;
}
return any;
}
/*
=item C<const char * get_neg_op(const char *op, int *n)>
Get negated form of operator. If no negated form is known, return NULL.
=cut
*/
PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
const char *
get_neg_op(ARGIN(const char *op), ARGOUT(int *n))
{
ASSERT_ARGS(get_neg_op)
PARROT_OBSERVER static const struct br_pairs {
PARROT_OBSERVER const char * const op;
PARROT_OBSERVER const char * const nop;
int n;
} br_pairs[] = {
{ "if", "unless", 2 },
{ "eq", "ne", 3 },
{ "gt", "le", 3 },
{ "ge", "lt", 3 },
};
size_t i;
for (i = 0; i < N_ELEMENTS(br_pairs); i++) {
*n = br_pairs[i].n;
if (STREQ(op, br_pairs[i].op))
return br_pairs[i].nop;
if (STREQ(op, br_pairs[i].nop))
return br_pairs[i].op;
}
return NULL;
}
/*
*
*/
/*
=item C<static int if_branch(imc_info_t *imcc, IMC_Unit *unit)>
Convert if/branch/label constructs of the form:
if cond L1
branch L2
L1
to the simpler negated form:
unless cond L2
=cut
*/
static int
if_branch(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
{
ASSERT_ARGS(if_branch)
Instruction *ins, *last;
int reg, changed = 0;
last = unit->instructions;
if (!last->next)
return changed;
IMCC_info(imcc, 2, "\tif_branch\n");
for (ins = last->next; ins;) {
if ((last->type & ITBRANCH) && /* if ...L1 */
(ins->type & IF_goto) && /* branch L2*/
STREQ(ins->opname, "branch") &&
(reg = get_branch_regno(last)) >= 0) {
SymReg * const br_dest = last->symregs[reg];
if (ins->next &&
(ins->next->type & ITLABEL) && /* L1 */
ins->next->symregs[0] == br_dest) {
const char * neg_op;
SymReg * const go = get_branch_reg(ins);
int args;
IMCC_debug(imcc, DEBUG_OPT1, "if_branch %s ... %s\n",
last->opname, br_dest->name);
/* find the negated op (e.g if->unless, ne->eq ... */
if ((neg_op = get_neg_op(last->opname, &args)) != NULL) {
Instruction * tmp;
last->symregs[reg] = go;
tmp = INS(imcc, unit, neg_op, "",
last->symregs, args, 0, 0);
last->op = tmp->op;
last->opsize = tmp->opsize;
mem_sys_free(last->opname);
last->opname = mem_sys_strdup(tmp->opname);
free_ins(tmp);
/* delete branch */
unit->ostat.deleted_ins++;
ins = delete_ins(unit, ins);
unit->ostat.if_branch++;
changed = 1;
}
} /* label found */
} /* branch detected */
last = ins;
ins = ins->next;
}
return changed;
}
/*
=item C<static int strength_reduce(imc_info_t *imcc, IMC_Unit *unit)>
strength_reduce ... rewrites e.g add Ix, Ix, y => add Ix, y
These are run after constant simplification, so it is
guaranteed that one operand is non constant if opsize == 4
=cut
*/
static int
strength_reduce(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
{
ASSERT_ARGS(strength_reduce)
Instruction *ins, *tmp;
SymReg *r;
int changes = 0;
FLOATVAL f;
op_lib_t *core_ops = PARROT_GET_CORE_OPLIB(imcc->interp);
IMCC_info(imcc, 2, "\tstrength_reduce\n");
for (ins = unit->instructions; ins; ins = ins->next) {
/*
* add Ix, Ix, Iy => add Ix, Iy
* add Ix, Iy, Ix => add Ix, Iy
* sub Ix, Ix, Iy => sub Ix, Iy
* mul Ix, Ix, Iy => sub Ix, Iy
* mul Ix, Iy, Ix => sub Ix, Iy
* div Ix, Ix, Iy => sub Ix, Iy
* fdiv Ix, Ix, Iy => sub Ix, Iy
* add Nx, Nx, Ny => add Nx, Ny
* add Nx, Ny, Nx => add Nx, Ny
* sub Nx, Nx, Ny => sub Nx, Ny
* mul Nx, Nx, Ny => sub Nx, Ny
* mul Nx, Ny, Nx => sub Nx, Ny
* div Nx, Nx, Ny => sub Nx, Ny
* fdiv Nx, Nx, Ny => sub Nx, Ny
*/
if (((ins->op == &core_ops->op_info_table[PARROT_OP_sub_i_i_i] ||
ins->op == &core_ops->op_info_table[PARROT_OP_sub_i_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_sub_i_ic_i] ||
ins->op == &core_ops->op_info_table[PARROT_OP_div_i_i_i] ||
ins->op == &core_ops->op_info_table[PARROT_OP_div_i_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_div_i_ic_i] ||
ins->op == &core_ops->op_info_table[PARROT_OP_fdiv_i_i_i] ||
ins->op == &core_ops->op_info_table[PARROT_OP_fdiv_i_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_fdiv_i_ic_i] ||
ins->op == &core_ops->op_info_table[PARROT_OP_sub_n_n_n] ||
ins->op == &core_ops->op_info_table[PARROT_OP_sub_n_n_nc] ||
ins->op == &core_ops->op_info_table[PARROT_OP_sub_n_nc_n] ||
ins->op == &core_ops->op_info_table[PARROT_OP_div_n_n_n] ||
ins->op == &core_ops->op_info_table[PARROT_OP_div_n_n_nc] ||
ins->op == &core_ops->op_info_table[PARROT_OP_div_n_nc_n] ||
ins->op == &core_ops->op_info_table[PARROT_OP_fdiv_n_n_n] ||
ins->op == &core_ops->op_info_table[PARROT_OP_fdiv_n_n_nc] ||
ins->op == &core_ops->op_info_table[PARROT_OP_fdiv_n_nc_n]) &&
ins->symregs[0] == ins->symregs[1])
|| ((ins->op == &core_ops->op_info_table[PARROT_OP_add_i_i_i] ||
ins->op == &core_ops->op_info_table[PARROT_OP_add_i_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_add_i_ic_i] ||
ins->op == &core_ops->op_info_table[PARROT_OP_mul_i_i_i] ||
ins->op == &core_ops->op_info_table[PARROT_OP_mul_i_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_mul_i_ic_i] ||
ins->op == &core_ops->op_info_table[PARROT_OP_add_n_n_n] ||
ins->op == &core_ops->op_info_table[PARROT_OP_add_n_n_nc] ||
ins->op == &core_ops->op_info_table[PARROT_OP_add_n_nc_n] ||
ins->op == &core_ops->op_info_table[PARROT_OP_mul_n_n_n] ||
ins->op == &core_ops->op_info_table[PARROT_OP_mul_n_n_nc] ||
ins->op == &core_ops->op_info_table[PARROT_OP_mul_n_nc_n]) &&
(ins->symregs[0] == ins->symregs[1] ||
ins->symregs[0] == ins->symregs[2]))) {
IMCC_debug(imcc, DEBUG_OPT1, "opt1 %d => ", ins);
if (ins->symregs[0] == ins->symregs[1]) {
ins->symregs[1] = ins->symregs[2];
}
tmp = INS(imcc, unit, ins->opname, "", ins->symregs, 2, 0, 0);
IMCC_debug(imcc, DEBUG_OPT1, "%d\n", tmp);
subst_ins(unit, ins, tmp, 1);
ins = tmp;
changes = 1;
}
/*
* add Ix, 0 => delete
* sub Ix, 0 => delete
* mul Ix, 1 => delete
* div Ix, 1 => delete
* fdiv Ix, 1 => delete
* add Nx, 0 => delete
* sub Nx, 0 => delete
* mul Nx, 1 => delete
* div Nx, 1 => delete
* fdiv Nx, 1 => delete
*/
if (((ins->op == &core_ops->op_info_table[PARROT_OP_add_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_sub_i_ic]) &&
IMCC_int_from_reg(imcc, ins->symregs[1]) == 0)
|| ((ins->op == &core_ops->op_info_table[PARROT_OP_mul_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_div_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_fdiv_i_ic]) &&
IMCC_int_from_reg(imcc, ins->symregs[1]) == 1)
|| ((ins->op == &core_ops->op_info_table[PARROT_OP_add_n_nc] ||
ins->op == &core_ops->op_info_table[PARROT_OP_sub_n_nc]) &&
(f = atof(ins->symregs[1]->name), FLOAT_IS_ZERO(f)))
|| ((ins->op == &core_ops->op_info_table[PARROT_OP_mul_n_nc] ||
ins->op == &core_ops->op_info_table[PARROT_OP_div_n_nc] ||
ins->op == &core_ops->op_info_table[PARROT_OP_fdiv_n_nc]) &&
atof(ins->symregs[1]->name) == 1.0)) {
IMCC_debug(imcc, DEBUG_OPT1, "opt1 %d => ", ins);
ins = delete_ins(unit, ins);
if (ins)
ins = ins->prev ? ins->prev : unit->instructions;
else
break;
IMCC_debug(imcc, DEBUG_OPT1, "deleted\n");
changes = 1;
continue;
}
/*
* add Ix, 1 => inc Ix
* add Nx, 1 => inc Nx
* sub Ix, 1 => dec Ix
* sub Nx, 1 => dec Nx
*/
if (((ins->op == &core_ops->op_info_table[PARROT_OP_add_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_sub_i_ic]) &&
IMCC_int_from_reg(imcc, ins->symregs[1]) == 1)
|| ((ins->op == &core_ops->op_info_table[PARROT_OP_add_n_nc] ||
ins->op == &core_ops->op_info_table[PARROT_OP_sub_n_nc]) &&
atof(ins->symregs[1]->name) == 1.0)) {
IMCC_debug(imcc, DEBUG_OPT1, "opt1 %d => ", ins);
--ins->symregs[1]->use_count;
if (ins->op == &core_ops->op_info_table[PARROT_OP_add_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_add_n_nc])
tmp = INS(imcc, unit, "inc", "", ins->symregs, 1, 0, 0);
else
tmp = INS(imcc, unit, "dec", "", ins->symregs, 1, 0, 0);
subst_ins(unit, ins, tmp, 1);
IMCC_debug(imcc, DEBUG_OPT1, "%d\n", tmp);
ins = tmp;
changes = 1;
continue;
}
/*
* add Ix, Iy, 0 => set Ix, Iy
* add Ix, 0, Iy => set Ix, Iy
* sub Ix, Iy, 0 => set Ix, Iy
* mul Ix, Iy, 1 => set Ix, Iy
* mul Ix, 1, Iy => set Ix, Iy
* div Ix, Iy, 1 => set Ix, Iy
* fdiv Ix, Iy, 1 => set Ix, Iy
* add Nx, Ny, 0 => set Nx, Ny
* add Nx, 0, Ny => set Nx, Ny
* sub Nx, Ny, 0 => set Nx, Ny
* mul Nx, Ny, 1 => set Nx, Ny
* mul Nx, 1, Ny => set Nx, Ny
* div Nx, Ny, 1 => set Nx, Ny
* fdiv Nx, Ny, 1 => set Nx, Ny
*/
if (((ins->op == &core_ops->op_info_table[PARROT_OP_add_i_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_sub_i_i_ic]) &&
IMCC_int_from_reg(imcc, ins->symregs[2]) == 0)
|| (ins->op == &core_ops->op_info_table[PARROT_OP_add_i_ic_i] &&
IMCC_int_from_reg(imcc, ins->symregs[1]) == 0)
|| ((ins->op == &core_ops->op_info_table[PARROT_OP_mul_i_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_div_i_i_ic] ||
ins->op == &core_ops->op_info_table[PARROT_OP_fdiv_i_i_ic]) &&
IMCC_int_from_reg(imcc, ins->symregs[2]) == 1)
|| (ins->op == &core_ops->op_info_table[PARROT_OP_mul_i_ic_i] &&
IMCC_int_from_reg(imcc, ins->symregs[1]) == 1)
|| ((ins->op == &core_ops->op_info_table[PARROT_OP_add_n_n_nc] ||
ins->op == &core_ops->op_info_table[PARROT_OP_sub_n_n_nc]) &&
(f = atof(ins->symregs[2]->name), FLOAT_IS_ZERO(f)))
|| (ins->op == &core_ops->op_info_table[PARROT_OP_add_n_nc_n] &&
(f = atof(ins->symregs[1]->name), FLOAT_IS_ZERO(f)))
|| ((ins->op == &core_ops->op_info_table[PARROT_OP_mul_n_n_nc] ||
ins->op == &core_ops->op_info_table[PARROT_OP_div_n_n_nc] ||
ins->op == &core_ops->op_info_table[PARROT_OP_fdiv_n_n_nc]) &&
atof(ins->symregs[2]->name) == 1.0)
|| (ins->op == &core_ops->op_info_table[PARROT_OP_mul_n_nc_n] &&
atof(ins->symregs[1]->name) == 1.0)) {
IMCC_debug(imcc, DEBUG_OPT1, "opt1 %d => ", ins);
if (ins->symregs[1]->type == VTCONST) {
--ins->symregs[1]->use_count;
ins->symregs[1] = ins->symregs[2];
}
else {
--ins->symregs[2]->use_count;
}
tmp = INS(imcc, unit, "set", "", ins->symregs, 2, 0, 0);
IMCC_debug(imcc, DEBUG_OPT1, "%d\n", tmp);
subst_ins(unit, ins, tmp, 1);
ins = tmp;
changes = 1;
continue;
}
/*
* mul Ix, Iy, 0 => set Ix, 0
* mul Ix, 0, Iy => set Ix, 0
* mul Ix, 0 => set Ix, 0
*/
if ((ins->op == &core_ops->op_info_table[PARROT_OP_mul_i_i_ic] &&
IMCC_int_from_reg(imcc, ins->symregs[2]) == 0)
|| ((ins->op == &core_ops->op_info_table[PARROT_OP_mul_i_ic_i] ||
ins->op == &core_ops->op_info_table[PARROT_OP_mul_i_ic]) &&
IMCC_int_from_reg(imcc, ins->symregs[1]) == 0)
|| (ins->op == &core_ops->op_info_table[PARROT_OP_mul_n_n_nc] &&
(f = atof(ins->symregs[2]->name), FLOAT_IS_ZERO(f)))
|| ((ins->op == &core_ops->op_info_table[PARROT_OP_mul_n_nc_n] ||
ins->op == &core_ops->op_info_table[PARROT_OP_mul_n_nc]) &&
(f = atof(ins->symregs[1]->name), FLOAT_IS_ZERO(f)))) {
IMCC_debug(imcc, DEBUG_OPT1, "opt1 %d => ", ins);
r = mk_const(imcc, "0", ins->symregs[0]->set);
--ins->symregs[1]->use_count;
if (ins->opsize == 4)
--ins->symregs[2]->use_count;
ins->symregs[1] = r;
tmp = INS(imcc, unit, "set", "", ins->symregs, 2, 0, 0);
IMCC_debug(imcc, DEBUG_OPT1, "%d\n", tmp);
subst_ins(unit, ins, tmp, 1);
ins = tmp;
changes = 1;
}
/*
* set Ix, 0 => null Ix
* set Nx, 0 => null Nx
*/
if ((ins->op == &core_ops->op_info_table[PARROT_OP_set_i_ic] &&
IMCC_int_from_reg(imcc, ins->symregs[1]) == 0)
|| (ins->op == &core_ops->op_info_table[PARROT_OP_set_n_nc] &&
(f = atof(ins->symregs[1]->name), FLOAT_IS_ZERO(f)) &&
ins->symregs[1]->name[0] != '-')) {
IMCC_debug(imcc, DEBUG_OPT1, "opt1 %d => ", ins);
--ins->symregs[1]->use_count;
tmp = INS(imcc, unit, "null", "", ins->symregs, 1, 0, 0);
subst_ins(unit, ins, tmp, 1);
IMCC_debug(imcc, DEBUG_OPT1, "%d\n", tmp);
ins = tmp;
changes = 1;
continue;
}
}
return changes;
}
/*
=item C<static int constant_propagation(imc_info_t *imcc, IMC_Unit *unit)>
Does conservative constant propagation.
This code will not propagate constants past labels or saves,
even though sometimes it may be safe.
=cut
*/
static int
constant_propagation(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
{
ASSERT_ARGS(constant_propagation)
Instruction *ins;
SymReg *c, *o;
int any = 0;
o = c = NULL; /* silence compiler uninit warning, but XXX better to handle flow well */
IMCC_info(imcc, 2, "\tconstant_propagation\n");
for (ins = unit->instructions; ins; ins = ins->next) {
int found = 0;
if (STREQ(ins->opname, "set") &&
ins->opsize == 3 && /* no keyed set */
ins->symregs[1]->type == VTCONST &&
ins->symregs[0]->set != 'P') { /* no PMC consts */
found = 1;
c = ins->symregs[1];
o = ins->symregs[0];
}
else if (STREQ(ins->opname, "null") && ins->symregs[0]->set == 'I') {
found = 1;
c = mk_const(imcc, "0", 'I');
o = ins->symregs[0];
} /* this would be good because 'set I0, 0' is reduced to 'null I0'
before it gets to us */
if (found) {
Instruction *ins2;
IMCC_debug(imcc, DEBUG_OPT2,
"propagating constant %d => \n", ins);
for (ins2 = ins->next; ins2; ins2 = ins2->next) {
int i;
if (ins2->bbindex != ins->bbindex)
/* restrict to within a basic block */
goto next_constant;
/* was opsize - 2, changed to n_r - 1
*/
for (i = ins2->symreg_count - 1; i >= 0; i--) {
if (STREQ(o->name, ins2->symregs[i]->name)) {
if (instruction_writes(ins2, ins2->symregs[i]))
goto next_constant;
else if (instruction_reads(ins2, ins2->symregs[i])) {
Instruction *tmp;
SymReg *old;
IMCC_debug(imcc, DEBUG_OPT2,
"\tpropagating into %d register %i",
ins2, i);
old = ins2->symregs[i];
ins2->symregs[i] = c;
/* first we try subst_constants for e.g. if 10 < 5 goto next*/
tmp = IMCC_subst_constants(imcc,
unit, ins2->opname, ins2->symregs, ins2->opsize,
&found);
if (found) {
const Instruction * const prev = ins2->prev;
if (prev) {
subst_ins(unit, ins2, tmp, 1);
any = 1;
IMCC_debug(imcc, DEBUG_OPT2,
" reduced to %d\n", tmp);
ins2 = prev->next;
}
}
else {
char fullname[128];
check_op(imcc, &ins2->op, fullname, ins2->opname,
ins2->symregs, ins2->symreg_count, ins2->keys);
if (!ins2->op) {
ins2->symregs[i] = old;
IMCC_debug(imcc, DEBUG_OPT2,
" - no %s\n", fullname);
}
else {
--old->use_count;
any = 1;
IMCC_debug(imcc, DEBUG_OPT2,
" -> %d\n", ins2);
}
}
}
}
}/* for (i ... )*/
}/* for (ins2 ... )*/
} /* if */
next_constant:;
}/*for (ins ... )*/
return any;
}
/*
=item C<Instruction * IMCC_subst_constants_umix(imc_info_t *imcc, IMC_Unit
*unit, const char *name, SymReg **r, int n)>
rewrite e.g. add_n_ic => add_n_nc
=cut
*/
PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
Instruction *
IMCC_subst_constants_umix(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit),
ARGIN(const char *name), ARGMOD(SymReg **r), int n)
{
ASSERT_ARGS(IMCC_subst_constants_umix)
Instruction *tmp;
PARROT_OBSERVER const char * const ops[] = {
"abs", "add", "div", "mul", "sub", "fdiv"
};
size_t i;
char b[128];
tmp = NULL;
for (i = 0; i < N_ELEMENTS(ops); i++) {
if (n == 3 &&
r[0]->set == 'N' &&
r[1]->type == VTCONST &&
r[1]->set == 'I' &&
STREQ(name, ops[i])) {
IMCC_debug(imcc, DEBUG_OPT1, "opt1 %s_nc_ic => ", name);
strcpy(b, r[1]->name);
r[1] = mk_const(imcc, b, 'N');
tmp = INS(imcc, unit, name, "", r, 2, 0, 0);
IMCC_debug(imcc, DEBUG_OPT1, "%d\n", tmp);
}
}
return tmp;
}
/*
=item C<static int eval_ins(imc_info_t *imcc, const char *op, size_t ops, SymReg
**r)>
Run one parrot instruction, registers are filled with the
according constants. If an exception occurs, return -1, aborting
this optimization: this lets the runtime handle any exceptions.
=cut
*/
PARROT_WARN_UNUSED_RESULT
static int
eval_ins(ARGMOD(imc_info_t *imcc), ARGIN(const char *op), size_t ops,
ARGIN(SymReg **r))
{
ASSERT_ARGS(eval_ins)
opcode_t eval[4], *pc;
int i;
op_info_t *op_info = (op_info_t *)Parrot_hash_get(imcc->interp, imcc->interp->op_hash, op);
if (!op_info || !STREQ(op_info->full_name, op))
IMCC_fatal(imcc, 1, "eval_ins: op '%s' not found\n", op);
/* now fill registers */
eval[0] = 0;
for (i = 0; i < op_info->op_count - 1; i++) {
switch (op_info->types[i]) {
case PARROT_ARG_IC:
PARROT_ASSERT(i && ops == (unsigned int)i);
/* set branch offset to zero */
eval[i + 1] = 0;
break;
case PARROT_ARG_I:
case PARROT_ARG_N:
case PARROT_ARG_S:
eval[i + 1] = i; /* regs used are I0, I1, I2 */
if (ops <= 2 || i) { /* fill source regs */
SymReg * const r_ = r[i]->type & VT_CONSTP ? r[i]->reg : r[i];
switch (r[i]->set) {
case 'I':
REG_INT(imcc->interp, i) = IMCC_int_from_reg(imcc, r_);
break;
case 'N':
{
STRING * const s = Parrot_str_new(imcc->interp, r_->name, 0);
REG_NUM(imcc->interp, i) = Parrot_str_to_num(imcc->interp, s);
}
break;
case 'S':
REG_STR(imcc->interp, i) = IMCC_string_from_reg(imcc, r_);
break;
default:
break;
}
}
break;
default:
IMCC_fatal(imcc, 1, "eval_ins"
"invalid arg #%d for op '%s' not found\n",
i, op);
}
}
/* eval the opcode */
new_runloop_jump_point(imcc->interp);
if (setjmp(imcc->interp->current_runloop->resume))
return -1;
pc = (OP_INFO_OPFUNC(op_info)) (eval, imcc->interp);
free_runloop_jump_point(imcc->interp);
/* the returned pc is either incremented by op_count or is eval,
* as the branch offset is 0 - return true if it branched
*/
PARROT_ASSERT(pc == eval + op_info->op_count || pc == eval);
return pc == eval;
}
/*
=item C<Instruction * IMCC_subst_constants(imc_info_t *imcc, IMC_Unit *unit,
const char *name, SymReg **r, int n, int *ok)>
rewrite e.g. add_n_nc_nc => set_n_nc
abs_i_ic => set_i_ic
eq_ic_ic_ic => branch_ic / delete
if_ic_ic => branch_ic / delete
=cut
*/
PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
Instruction *
IMCC_subst_constants(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit),
ARGIN(const char *name), ARGMOD(SymReg **r), int n, ARGOUT(int *ok))
{
ASSERT_ARGS(IMCC_subst_constants)
Instruction *tmp;
PARROT_OBSERVER const char * const ops[] = {
"add", "sub", "mul", "div", "fdiv", "pow",
"cmod", "mod", "atan",
"shr", "shl", "lsr",
"gcd", "lcm",
"band", "bor", "bxor",
"bands", "bors", "bxors",
"and", "or", "xor",
"iseq", "isne", "islt", "isle", "isgt", "isge", "cmp", "concat"
};
PARROT_OBSERVER const char * const ops2[] = {
"abs", "neg", "not", "fact", "sqrt", "ceil", "floor"
"acos", "asec", "asin",
"atan", "cos", "cosh", "exp", "ln", "log10", "log2", "sec",
"sech", "sin", "sinh", "tan", "tanh", "fact"
};
PARROT_OBSERVER const char * const ops3[] = {
"eq", "ne", "gt", "ge", "lt", "le"
};
PARROT_OBSERVER const char * const ops4[] = {
"if", "unless"
};
size_t i;
char op[20];
const char *fmt = FLOATVAL_FMT;
const char *debug_fmt = NULL; /* gcc -O uninit warn */
int found, branched;
tmp = NULL;
found = 0;
for (i = 0; i < N_ELEMENTS(ops); i++) {
if (n == 4 &&
r[1]->type & (VTCONST|VT_CONSTP) &&
r[2]->type & (VTCONST|VT_CONSTP) &&
STREQ(name, ops[i])) {
found = 4;
/*
* create instruction e.g. add_i_ic_ic => add_i_i_i
*/
snprintf(op, sizeof (op), "%s_%c_%c_%c", name, tolower((unsigned char)r[0]->set),
tolower((unsigned char)r[1]->set), tolower((unsigned char)r[2]->set));
debug_fmt = "opt %s_x_xc_xc => ";
break;
}
}
for (i = 0; !found && i < N_ELEMENTS(ops2); i++) {
/*
* abs_i_ic ...
*/
if (n == 3) {
PARROT_ASSERT(r[1]);
if (r[1]->type & (VTCONST|VT_CONSTP) &&
STREQ(name, ops2[i])) {
found = 3;
snprintf(op, sizeof (op), "%s_%c_%c", name, tolower((unsigned char)r[0]->set),
tolower((unsigned char)r[1]->set));
debug_fmt = "opt %s_x_xc => ";
break;
}
}
}
for (i = 0; !found && i < N_ELEMENTS(ops3); i++) {
/*
* eq_xc_xc_labelc ...
*/
if (n == 4 &&
r[0]->type & (VTCONST|VT_CONSTP) &&
r[1]->type & (VTCONST|VT_CONSTP) &&
STREQ(name, ops3[i])) {
found = 2;
snprintf(op, sizeof (op), "%s_%c_%c_ic", name, tolower((unsigned char)r[0]->set),
tolower((unsigned char)r[1]->set));
debug_fmt = "opt %s_xc_xc_ic => ";
break;
}
}
for (i = 0; !found && i < N_ELEMENTS(ops4); i++) {
/*
* if_xc_labelc, unless
*/
if (n == 3 &&
r[0]->type & (VTCONST|VT_CONSTP) &&
STREQ(name, ops4[i])) {
found = 1;
snprintf(op, sizeof (op), "%s_%c_ic", name, tolower((unsigned char)r[0]->set));
debug_fmt = "opt %s_xc_ic => ";
break;
}
}
if (!found) {
*ok = 0;
return NULL;
}