//Control flow struct optimizations.
//Transform follow struct to do-while loop
//
// LABEL:
// IR-List
// IF DET
// GOTO LABEL
// ...(DEAD CODE)
// ELSE
// FALSE-PART
// ENDIF
//
//is replace by
//
// DO {
// IR-List
// } WHILE DET
// FALSE-PART
bool IR_CFS_OPT::transformToDoWhile(IR ** head, IR * ir)
{
ASSERT(head != NULL && *head != NULL, ("invalid parameter"));
if (!ir->is_lab()) { return false; }
for (IR * t = ir; t != NULL; t = t->get_next()) {
if (!t->is_if()) { continue; }
if (IF_truebody(t) != NULL &&
IF_truebody(t)->is_goto() &&
isSameLabel(LAB_lab(ir), GOTO_lab(IF_truebody(t)))) {
//Start transform.
IR * dowhile = m_ru->allocIR(IR_DO_WHILE);
LOOP_det(dowhile) = m_ru->dupIRTree(LOOP_det(t));
IR * if_stmt = t;
t = ir->get_next();
while (t != NULL && t != if_stmt) {
IR * c = t;
t = t->get_next();
xcom::remove(head, c);
xcom::add_next(&LOOP_body(dowhile), c);
}
ASSERT(t == if_stmt, ("illegal IR layout"));
xcom::remove(head, if_stmt);
if (IF_falsebody(if_stmt)) {
xcom::add_next(&dowhile, IF_falsebody(if_stmt));
IF_falsebody(if_stmt) = NULL;
}
xcom::insertafter(&ir, dowhile);
m_ru->freeIRTree(if_stmt); //free IF
xcom::remove(head, ir);
m_ru->freeIRTree(ir); //free LABEL
return true;
}
}
return false;
}
/*
Control flow struct optimizations.
Transform follow struct to do-while loop
LABEL:
IR-LIST
IF DET
GOTO LABEL
...(DEAD CODE)
ELSE
FALSE-PART
ENDIF
is replace by
DO {
IR-LIST
} WHILE DET
FALSE-PART
*/
bool IR_CFS_OPT::trans_to_do_while_loop(IR ** head, IR * ir)
{
IS_TRUE(head != NULL && *head != NULL, ("invalid parameter"));
if (ir->is_lab()) {
IR * t = ir;
LABEL_INFO * li = LAB_lab(ir);
while (t != NULL) {
if (IR_type(t) == IR_IF) {
if (IF_truebody(t) != NULL &&
IR_type(IF_truebody(t)) == IR_GOTO &&
is_same_label(LAB_lab(ir), GOTO_lab(IF_truebody(t)))) {
//start transform...
IR * dowhile = m_ru->new_ir(IR_DO_WHILE);
LOOP_det(dowhile) = m_ru->dup_irs(LOOP_det(t));
IR * if_stmt = t;
t = IR_next(ir);
while (t != NULL && t != if_stmt) {
IR * c = t;
t = IR_next(t);
remove(head, c);
add_next(&LOOP_body(dowhile), c);
}
IS_TRUE(t == if_stmt, ("???"));
remove(head, if_stmt);
if (IF_falsebody(if_stmt)) {
add_next(&dowhile, IF_falsebody(if_stmt));
IF_falsebody(if_stmt) = NULL;
}
insertafter(&ir, dowhile);
m_ru->free_irs(if_stmt); //free IF
remove(head, ir);
m_ru->free_irs(ir); //free LABEL
return true;
}
}
t = IR_next(t);
}
}
return false;
}
//The followed forms
// if (cond) {
//
// } else {
// IR-list
// }
//
//is replaced by
//
// if (!cond) {
// IR-list
// }
bool IR_CFS_OPT::transformIf2(IR ** head, IR * ir)
{
ASSERT(head && *head, ("invalid parameter"));
if (ir == NULL || !ir->is_if()) { return false; }
//Check true part
if (IF_truebody(ir) == NULL) {
if (IF_falsebody(ir) == NULL) {
xcom::remove(head, ir);
m_ru->freeIRTree(ir);
return true;
}
m_ru->invertCondition(&IF_det(ir));
IF_truebody(ir) = IF_falsebody(ir);
IF_falsebody(ir) = NULL;
return true;
}
return false;
}
/* The followed forms
if (cond) {
} else {
IR-list
}
is replaced by
if (!cond) {
IR-list
} */
bool IR_CFS_OPT::trans_if2(IR ** head, IR * ir)
{
IS_TRUE(head && *head, ("invalid parameter"));
if (ir == NULL || IR_type(ir) != IR_IF) { return false; }
//Check true part
if (!IF_truebody(ir)) {
if (IF_falsebody(ir) == NULL) {
remove(head, ir);
m_ru->free_irs(ir);
return true;
}
m_ru->invert_cond(&IF_det(ir));
IF_truebody(ir) = IF_falsebody(ir);
IF_falsebody(ir) = NULL;
return true;
}
return false;
}
bool IR_CFS_OPT::CfsOpt(
IN OUT IR ** ir_list,
SimpCtx const& sc)
{
bool change = false;
for (IR * ir = *ir_list; ir != NULL;) {
if (transformToDoWhile(ir_list, ir)) {
change = true;
ir = *ir_list;
continue;
}
if (ir->is_if() && transformIf1(ir_list, ir)) {
change = true;
ir = *ir_list;
continue;
}
if (ir->is_if() && transformIf2(ir_list, ir)) {
change = true;
ir = *ir_list;
continue;
}
if (ir->is_if() && transformIf3(ir_list, ir)) {
change = true;
ir = *ir_list;
continue;
}
switch (ir->get_code()) {
case IR_IF:
if (hoistIf(ir_list, ir)) {
change = true;
ir = *ir_list;
continue;
}
if (CfsOpt(&IF_truebody(ir), sc)) {
change = true;
ir = *ir_list;
continue;
}
if (CfsOpt(&IF_falsebody(ir), sc)) {
change = true;
ir = *ir_list;
continue;
}
break;
case IR_DO_WHILE:
case IR_WHILE_DO:
case IR_DO_LOOP:
if (hoistLoop(ir_list, ir)) {
change = true;
ir = *ir_list;
continue;
}
if (CfsOpt(&LOOP_body(ir), sc)) {
change = true;
ir = *ir_list;
continue;
}
break;
case IR_SWITCH:
if (CfsOpt(&SWITCH_body(ir), sc)) {
change = true;
ir = *ir_list;
continue;
}
break;
default:;
} //end switch
ir = ir->get_next();
}
return change;
}
//The followed forms
// x is signed
// IF(x > 0x7FFFFFFF) {a=1} ELSE {b=1} => b=1
// IF(x < 0x80000000) {a=1} ELSE {b=1} => b=1
//
// x is unsigned
// IF(x > 0xFFFFFFFF){a=1} ELSE {b=1} => b=1
// IF(x < 0x0) {a=1} ELSE {b=1} => b=1
bool IR_CFS_OPT::transformIf3(IR ** head, IR * ir)
{
ASSERT(head && *head, ("invalid parameter"));
if (ir == NULL || !ir->is_if()) { return false; }
IR * det = IF_det(ir);
if (det->is_gt()) {
IR * opnd0 = BIN_opnd0(det);
IR * opnd1 = BIN_opnd1(det);
if (opnd0->is_ld() &&
opnd0->is_int() &&
opnd1->is_const() &&
opnd1->is_int() &&
m_ru->getIntegerInDataTypeValueRange(opnd1) ==
m_ru->getMaxInteger(m_tm->get_dtype_bitsize(
TY_dtype(opnd1->get_type())), opnd1->is_signed())) {
//e.g:
//x is unsigned, if(x>0xFFFFFFFF) {a=1} else {b=1} => b=1
//x is signed, if(x>0x7FFFFFFF) {a=1} else {b=1} => b=1
IR * allocIR = NULL;
if (IF_falsebody(ir) != NULL) {
allocIR = m_ru->dupIRTree(IF_falsebody(ir));
}
xcom::replace(head, ir, allocIR);
if (allocIR != NULL) {
IR_parent(allocIR) = IR_parent(ir);
}
m_ru->freeIRTree(ir);
return true;
}
} else if (det->is_lt()) {
IR * opnd0 = BIN_opnd0(det);
IR * opnd1 = BIN_opnd1(det);
if (opnd0->is_ld() &&
opnd0->is_int() &&
opnd1->is_const() &&
opnd1->is_int() &&
m_ru->getIntegerInDataTypeValueRange(opnd1) ==
m_ru->getMinInteger(m_tm->get_dtype_bitsize(
TY_dtype(opnd1->get_type())), opnd1->is_signed())) {
//x is signed, IF(x < 0x80000000) {a=1} ELSE {b=1} => b=1
IR * allocIR = NULL;
if (IF_falsebody(ir) != NULL) {
allocIR = m_ru->dupIRTree(IF_falsebody(ir));
}
xcom::replace(head, ir, allocIR);
if (allocIR != NULL) {
IR_parent(allocIR) = IR_parent(ir);
}
m_ru->freeIRTree(ir);
return true;
} else if (opnd0->is_ld() &&
opnd1->is_const() &&
opnd0->is_uint() &&
CONST_int_val(opnd1) == 0) {
//x is unsigned, if(x<0) {a=1} else {b=1} => b=1
IR * allocIR = NULL;
if (IF_falsebody(ir) != NULL) {
allocIR = m_ru->dupIRTree(IF_falsebody(ir));
}
xcom::replace(head, ir, allocIR);
if (allocIR != NULL) {
IR_parent(allocIR) = IR_parent(ir);
}
m_ru->freeIRTree(ir);
return true;
}
}
return false;
}
bool IR_CFS_OPT::perform_cfs_optimization(IN OUT IR ** ir_list,
IN SIMP_CTX const& sc)
{
bool change = false;
for (IR * ir = *ir_list; ir != NULL;) {
if (trans_to_do_while_loop(ir_list, ir)) {
change = true;
ir = *ir_list;
continue;
}
if (IR_type(ir) == IR_IF && trans_if1(ir_list, ir)) {
change = true;
ir = *ir_list;
continue;
}
if (IR_type(ir) == IR_IF && trans_if2(ir_list, ir)) {
change = true;
ir = *ir_list;
continue;
}
if (IR_type(ir) == IR_IF && trans_if3(ir_list, ir)) {
change = true;
ir = *ir_list;
continue;
}
switch (IR_type(ir)) {
case IR_IF:
if (hoist_if(ir_list, ir)) {
change = true;
ir = *ir_list;
continue;
}
if (perform_cfs_optimization(&IF_truebody(ir), sc)) {
change = true;
ir = *ir_list;
continue;
}
if (perform_cfs_optimization(&IF_falsebody(ir), sc)) {
change = true;
ir = *ir_list;
continue;
}
break;
case IR_DO_WHILE:
case IR_WHILE_DO:
case IR_DO_LOOP:
if (hoist_loop(ir_list, ir)) {
change = true;
ir = *ir_list;
continue;
}
if (perform_cfs_optimization(&LOOP_body(ir), sc)) {
change = true;
ir = *ir_list;
continue;
}
break;
case IR_SWITCH:
if (perform_cfs_optimization(&SWITCH_body(ir), sc)) {
change = true;
ir = *ir_list;
continue;
}
break;
default:;
} //end switch
ir = IR_next(ir);
}
return change;
}
/* The followed forms
x is signed
IF(x > 0x7FFFFFFF) {a=1} ELSE {b=1} => b=1
IF(x < 0x80000000) {a=1} ELSE {b=1} => b=1
x is unsigned
IF(x > 0xFFFFFFFF){a=1} ELSE {b=1} => b=1
IF(x < 0x0) {a=1} ELSE {b=1} => b=1 */
bool IR_CFS_OPT::trans_if3(IR ** head, IR * ir)
{
IS_TRUE(head && *head, ("invalid parameter"));
if (ir == NULL || IR_type(ir) != IR_IF) { return false; }
IR * det = IF_det(ir);
if (IR_type(det) == IR_GT) {
IR * opnd0 = BIN_opnd0(det);
IR * opnd1 = BIN_opnd1(det);
DTD const* op0_rty = opnd0->get_dtd(m_dm);
DTD const* op1_rty = opnd1->get_dtd(m_dm);
if (IR_type(opnd0) == IR_LD &&
opnd1->is_const() &&
opnd0->is_int(m_dm) &&
CONST_int_val(opnd1) == MAX_INT_VALUE) {
//x is signed, if(x>0x7FFFFFFF) {a=1} else {b=1} => b=1
IR * new_ir = NULL;
if (IF_falsebody(ir)) {
new_ir = m_ru->dup_irs(IF_falsebody(ir));
}
replace(head, ir, new_ir);
//Revise IR_parent.
IR_parent(new_ir) = IR_parent(ir);
m_ru->free_irs(ir);
return true;
} else if (IR_type(opnd0) == IR_LD &&
IR_is_const(opnd1) &&
opnd0->is_uint(m_dm) &&
CONST_int_val(opnd1) == MAX_UINT_VALUE) {
//x is unsigned, if(x>0xFFFFFFFF) {a=1} else {b=1} => b=1
IR * new_ir = NULL;
if (IF_falsebody(ir)) {
new_ir = m_ru->dup_irs(IF_falsebody(ir));
}
replace(head, ir, new_ir);
//Revise IR_parent.
IR_parent(new_ir) = IR_parent(ir);
m_ru->free_irs(ir);
return true;
}
} else if (IR_type(det) == IR_LT) {
IR * opnd0 = BIN_opnd0(det);
IR * opnd1 = BIN_opnd1(det);
DTD const* op0_rty = opnd0->get_dtd(m_dm);
DTD const* op1_rty = opnd1->get_dtd(m_dm);
if (IR_type(opnd0) == IR_LD &&
IR_is_const(opnd1) &&
opnd0->is_int(m_dm) &&
CONST_int_val(opnd1) == MIN_INT_VALUE) {
//x is signed, IF(x < 0x80000000) {a=1} ELSE {b=1} => b=1
IR * new_ir = NULL;
if (IF_falsebody(ir)) {
new_ir = m_ru->dup_irs(IF_falsebody(ir));
}
replace(head, ir, new_ir);
m_ru->free_irs(ir);
return true;
} else if (IR_type(opnd0) == IR_LD &&
IR_is_const(opnd1) &&
opnd0->is_uint(m_dm) &&
CONST_int_val(opnd1) == 0) {
//x is unsigned, if(x<0) {a=1} else {b=1} => b=1
IR * new_ir = NULL;
if (IF_falsebody(ir)) {
new_ir = m_ru->dup_irs(IF_falsebody(ir));
}
replace(head, ir, new_ir);
//Revise IR_parent.
IR_parent(new_ir) = IR_parent(ir);
m_ru->free_irs(ir);
return true;
}
}
return false;
}
