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8032894: Remove dead code in Pressure::lower

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Remove dead code in Pressure::lower

Reviewed-by: kvn, roland
This commit is contained in:
Niclas Adlertz 2014-02-25 10:26:21 +01:00
parent 0b85ee832e
commit e3931e81eb
2 changed files with 58 additions and 30 deletions
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46
hotspot/src/share/vm/opto/chaitin.hpp
View File

@ -501,8 +501,9 @@ private:
// Used for aggressive coalescing.
void build_ifg_virtual( );
// used when computing the register pressure for each block in the CFG. This
// is done during IFG creation.
class Pressure {
public:
// keeps track of the register pressure at the current
// instruction (used when stepping backwards in the block)
uint _current_pressure;
@ -518,6 +519,7 @@ private:
// number of live ranges that constitute high register pressure
const uint _high_pressure_limit;
public:
// lower the register pressure and look for a low to high pressure
// transition
@ -525,9 +527,6 @@ private:
_current_pressure -= lrg.reg_pressure();
if (_current_pressure == _high_pressure_limit) {
_high_pressure_index = location;
if (_current_pressure > _final_pressure) {
_final_pressure = _current_pressure + 1;
}
}
}
@ -540,6 +539,45 @@ private:
}
}
uint high_pressure_index() const {
return _high_pressure_index;
}
uint final_pressure() const {
return _final_pressure;
}
uint current_pressure() const {
return _current_pressure;
}
uint high_pressure_limit() const {
return _high_pressure_limit;
}
void lower_high_pressure_index() {
_high_pressure_index--;
}
void set_high_pressure_index_to_block_start() {
_high_pressure_index = 0;
}
void check_pressure_at_fatproj(uint fatproj_location, RegMask& fatproj_mask) {
// this pressure is only valid at this instruction, i.e. we don't need to lower
// the register pressure since the fat proj was never live before (going backwards)
uint new_pressure = current_pressure() + fatproj_mask.Size();
if (new_pressure > final_pressure()) {
_final_pressure = new_pressure;
}
// if we were at a low pressure and now and the fat proj is at high pressure, record the fat proj location
// as coming from a low to high (to low again)
if (current_pressure() <= high_pressure_limit() && new_pressure > high_pressure_limit()) {
_high_pressure_index = fatproj_location;
}
}
Pressure(uint high_pressure_index, uint high_pressure_limit)
: _current_pressure(0)
, _high_pressure_index(high_pressure_index)

42
hotspot/src/share/vm/opto/ifg.cpp
View File

@ -439,8 +439,8 @@ void PhaseChaitin::lower_pressure(Block* b, uint location, LRG& lrg, IndexSet* l
}
}
}
assert(int_pressure._current_pressure == count_int_pressure(liveout), "the int pressure is incorrect");
assert(float_pressure._current_pressure == count_float_pressure(liveout), "the float pressure is incorrect");
assert(int_pressure.current_pressure() == count_int_pressure(liveout), "the int pressure is incorrect");
assert(float_pressure.current_pressure() == count_float_pressure(liveout), "the float pressure is incorrect");
}
/* Go to the first non-phi index in a block */
@ -513,8 +513,8 @@ void PhaseChaitin::compute_initial_block_pressure(Block* b, IndexSet* liveout, P
raise_pressure(b, lrg, int_pressure, float_pressure);
lid = elements.next();
}
assert(int_pressure._current_pressure == count_int_pressure(liveout), "the int pressure is incorrect");
assert(float_pressure._current_pressure == count_float_pressure(liveout), "the float pressure is incorrect");
assert(int_pressure.current_pressure() == count_int_pressure(liveout), "the int pressure is incorrect");
assert(float_pressure.current_pressure() == count_float_pressure(liveout), "the float pressure is incorrect");
}
/*
@ -548,17 +548,7 @@ bool PhaseChaitin::remove_node_if_not_used(Block* b, uint location, Node* n, uin
void PhaseChaitin::check_for_high_pressure_transition_at_fatproj(uint& block_reg_pressure, uint location, LRG& lrg, Pressure& pressure, const int op_regtype) {
RegMask mask_tmp = lrg.mask();
mask_tmp.AND(*Matcher::idealreg2regmask[op_regtype]);
// this pressure is only valid at this instruction, i.e. we don't need to lower
// the register pressure since the fat proj was never live before (going backwards)
uint new_pressure = pressure._current_pressure + mask_tmp.Size();
if (new_pressure > pressure._final_pressure) {
pressure._final_pressure = new_pressure;
}
// if we were at a low pressure and now at the fat proj is at high pressure, record the fat proj location
// as coming from a low to high (to low again)
if (pressure._current_pressure <= pressure._high_pressure_limit && new_pressure > pressure._high_pressure_limit) {
pressure._high_pressure_index = location;
}
pressure.check_pressure_at_fatproj(location, mask_tmp);
}
/*
@ -700,8 +690,8 @@ void PhaseChaitin::add_input_to_liveout(Block* b, Node* n, IndexSet* liveout, do
// Newly live things assumed live from here to top of block
lrg._area += cost;
raise_pressure(b, lrg, int_pressure, float_pressure);
assert(int_pressure._current_pressure == count_int_pressure(liveout), "the int pressure is incorrect");
assert(float_pressure._current_pressure == count_float_pressure(liveout), "the float pressure is incorrect");
assert(int_pressure.current_pressure() == count_int_pressure(liveout), "the int pressure is incorrect");
assert(float_pressure.current_pressure() == count_float_pressure(liveout), "the float pressure is incorrect");
}
assert(!(lrg._area < 0.0), "negative spill area" );
}
@ -710,13 +700,13 @@ void PhaseChaitin::add_input_to_liveout(Block* b, Node* n, IndexSet* liveout, do
/*
* If we run off the top of the block with high pressure just record that the
* whole block is high pressure. (Even though we might have a transition
* lower down in the block)
* later down in the block)
*/
void PhaseChaitin::check_for_high_pressure_block(Pressure& pressure) {
// current pressure now means the pressure before the first instruction in the block
// (since we have stepped through all instructions backwards)
if (pressure._current_pressure > pressure._high_pressure_limit) {
pressure._high_pressure_index = 0;
if (pressure.current_pressure() > pressure.high_pressure_limit()) {
pressure.set_high_pressure_index_to_block_start();
}
}
@ -725,7 +715,7 @@ void PhaseChaitin::check_for_high_pressure_block(Pressure& pressure) {
* and set the high pressure index for the block
*/
void PhaseChaitin::adjust_high_pressure_index(Block* b, uint& block_hrp_index, Pressure& pressure) {
uint i = pressure._high_pressure_index;
uint i = pressure.high_pressure_index();
if (i < b->number_of_nodes() && i < b->end_idx() + 1) {
Node* cur = b->get_node(i);
while (cur->is_Proj() || (cur->is_MachNullCheck()) || cur->is_Catch()) {
@ -789,8 +779,8 @@ uint PhaseChaitin::build_ifg_physical( ResourceArea *a ) {
if (!liveout.member(lid) && n->Opcode() != Op_SafePoint) {
if (remove_node_if_not_used(block, location, n, lid, &liveout)) {
float_pressure._high_pressure_index--;
int_pressure._high_pressure_index--;
float_pressure.lower_high_pressure_index();
int_pressure.lower_high_pressure_index();
continue;
}
if (lrg._fat_proj) {
@ -837,13 +827,13 @@ uint PhaseChaitin::build_ifg_physical( ResourceArea *a ) {
adjust_high_pressure_index(block, block->_ihrp_index, int_pressure);
adjust_high_pressure_index(block, block->_fhrp_index, float_pressure);
// set the final_pressure as the register pressure for the block
block->_reg_pressure = int_pressure._final_pressure;
block->_freg_pressure = float_pressure._final_pressure;
block->_reg_pressure = int_pressure.final_pressure();
block->_freg_pressure = float_pressure.final_pressure();
#ifndef PRODUCT
// Gather Register Pressure Statistics
if (PrintOptoStatistics) {
if (block->_reg_pressure > int_pressure._high_pressure_limit || block->_freg_pressure > float_pressure._high_pressure_limit) {
if (block->_reg_pressure > int_pressure.high_pressure_limit() || block->_freg_pressure > float_pressure.high_pressure_limit()) {
_high_pressure++;
} else {
_low_pressure++;