truffle: src/share/vm/c1/c1_ValueMap.cpp comparison

comparison src/share/vm/c1/c1_ValueMap.cpp @ 8860:46f6f063b272

7153771: array bound check elimination for c1 Summary: when possible optimize out array bound checks, inserting predicates when needed. Reviewed-by: never, kvn, twisti Contributed-by: thomaswue <thomas.wuerthinger@oracle.com>

author	roland
date	Thu, 21 Mar 2013 09:27:54 +0100
parents	b9a9ed0f8eeb
children	84ab5667f290

comparison

equal deleted inserted replaced

-:98f3af397705
+:46f6f063b272
 #include "precompiled.hpp"
 #include "c1/c1_Canonicalizer.hpp"
 #include "c1/c1_IR.hpp"
 #include "c1/c1_ValueMap.hpp"
+#include "c1/c1_ValueStack.hpp"
 #include "utilities/bitMap.inline.hpp"
 #ifndef PRODUCT
 int ValueMap::_number_of_finds = 0;
 int ValueMap::_number_of_hits = 0;
 LoadField* lf = value->as_LoadField();                                                 \
 bool must_kill = lf != NULL                                                            \
 && lf->field()->holder() == field->holder()                           \
 && (all_offsets || lf->field()->offset() == field->offset());
-#define MUST_KILL_EXCEPTION(must_kill, entry, value)                                     \
-assert(entry->nesting() < nesting(), "must not find bigger nesting than current");     \
-bool must_kill = (entry->nesting() == nesting() - 1);
 void ValueMap::kill_memory() {
 GENERIC_KILL_VALUE(MUST_KILL_MEMORY);
 }
 }
 void ValueMap::kill_field(ciField* field, bool all_offsets) {
 GENERIC_KILL_VALUE(MUST_KILL_FIELD);
 }
-void ValueMap::kill_exception() {
-GENERIC_KILL_VALUE(MUST_KILL_EXCEPTION);
-}
 void ValueMap::kill_map(ValueMap* map) {
 assert(is_global_value_numbering(), "only for global value numbering");
 _killed_values.set_union(&map->_killed_values);
 }
 class ShortLoopOptimizer : public ValueNumberingVisitor {
 private:
 GlobalValueNumbering* _gvn;
 BlockList             _loop_blocks;
 bool                  _too_complicated_loop;
+bool                  _has_field_store[T_ARRAY + 1];
+bool                  _has_indexed_store[T_ARRAY + 1];
 // simplified access to methods of GlobalValueNumbering
 ValueMap* current_map()                        { return _gvn->current_map(); }
 ValueMap* value_map_of(BlockBegin* block)      { return _gvn->value_map_of(block); }
 // implementation for abstract methods of ValueNumberingVisitor
 void      kill_memory()                                 { _too_complicated_loop = true; }
-void      kill_field(ciField* field, bool all_offsets)  { current_map()->kill_field(field, all_offsets); };
+void      kill_field(ciField* field, bool all_offsets)  {
-void      kill_array(ValueType* type)                   { current_map()->kill_array(type); };
+current_map()->kill_field(field, all_offsets);
+assert(field->type()->basic_type() >= 0 && field->type()->basic_type() <= T_ARRAY, "Invalid type");
+_has_field_store[field->type()->basic_type()] = true;
+}
+void      kill_array(ValueType* type)                   {
+current_map()->kill_array(type);
+BasicType basic_type = as_BasicType(type); assert(basic_type >= 0 && basic_type <= T_ARRAY, "Invalid type");
+_has_indexed_store[basic_type] = true;
+}
 public:
 ShortLoopOptimizer(GlobalValueNumbering* gvn)
 : _gvn(gvn)
 , _loop_blocks(ValueMapMaxLoopSize)
 , _too_complicated_loop(false)
 {
+for (int i=0; i<= T_ARRAY; i++){
+_has_field_store[i] = false;
+_has_indexed_store[i] = false;
+}
+}
+bool has_field_store(BasicType type) {
+assert(type >= 0 && type <= T_ARRAY, "Invalid type");
+return _has_field_store[type];
+}
+bool has_indexed_store(BasicType type) {
+assert(type >= 0 && type <= T_ARRAY, "Invalid type");
+return _has_indexed_store[type];
 }
 bool process(BlockBegin* loop_header);
 };
+class LoopInvariantCodeMotion : public StackObj  {
+private:
+GlobalValueNumbering* _gvn;
+ShortLoopOptimizer*   _short_loop_optimizer;
+Instruction*          _insertion_point;
+ValueStack *          _state;
+void set_invariant(Value v) const    { _gvn->set_processed(v); }
+bool is_invariant(Value v) const     { return _gvn->is_processed(v); }
+void process_block(BlockBegin* block);
+public:
+LoopInvariantCodeMotion(ShortLoopOptimizer *slo, GlobalValueNumbering* gvn, BlockBegin* loop_header, BlockList* loop_blocks);
+};
+LoopInvariantCodeMotion::LoopInvariantCodeMotion(ShortLoopOptimizer *slo, GlobalValueNumbering* gvn, BlockBegin* loop_header, BlockList* loop_blocks)
+: _gvn(gvn), _short_loop_optimizer(slo) {
+TRACE_VALUE_NUMBERING(tty->print_cr("using loop invariant code motion loop_header = %d", loop_header->block_id()));
+TRACE_VALUE_NUMBERING(tty->print_cr("** loop invariant code motion for short loop B%d", loop_header->block_id()));
+BlockBegin* insertion_block = loop_header->dominator();
+if (insertion_block->number_of_preds() == 0) {
+return;  // only the entry block does not have a predecessor
+}
+assert(insertion_block->end()->as_Base() == NULL, "cannot insert into entry block");
+_insertion_point = insertion_block->end()->prev();
+BlockEnd *block_end = insertion_block->end();
+_state = block_end->state_before();
+if (!_state) {
+// If, TableSwitch and LookupSwitch always have state_before when
+// loop invariant code motion happens..
+assert(block_end->as_Goto(), "Block has to be goto");
+_state = block_end->state();
+}
+// the loop_blocks are filled by going backward from the loop header, so this processing order is best
+assert(loop_blocks->at(0) == loop_header, "loop header must be first loop block");
+process_block(loop_header);
+for (int i = loop_blocks->length() - 1; i >= 1; i--) {
+process_block(loop_blocks->at(i));
+}
+}
+void LoopInvariantCodeMotion::process_block(BlockBegin* block) {
+TRACE_VALUE_NUMBERING(tty->print_cr("processing block B%d", block->block_id()));
+Instruction* prev = block;
+Instruction* cur = block->next();
+while (cur != NULL) {
+// determine if cur instruction is loop invariant
+// only selected instruction types are processed here
+bool cur_invariant = false;
+if (cur->as_Constant() != NULL) {
+cur_invariant = !cur->can_trap();
+} else if (cur->as_ArithmeticOp() != NULL || cur->as_LogicOp() != NULL || cur->as_ShiftOp() != NULL) {
+assert(cur->as_Op2() != NULL, "must be Op2");
+Op2* op2 = (Op2*)cur;
+cur_invariant = !op2->can_trap() && is_invariant(op2->x()) && is_invariant(op2->y());
+} else if (cur->as_LoadField() != NULL) {
+LoadField* lf = (LoadField*)cur;
+// deoptimizes on NullPointerException
+cur_invariant = !lf->needs_patching() && !lf->field()->is_volatile() && !_short_loop_optimizer->has_field_store(lf->field()->type()->basic_type()) && is_invariant(lf->obj());
+} else if (cur->as_ArrayLength() != NULL) {
+ArrayLength *length = cur->as_ArrayLength();
+cur_invariant = is_invariant(length->array());
+} else if (cur->as_LoadIndexed() != NULL) {
+LoadIndexed *li = (LoadIndexed *)cur->as_LoadIndexed();
+cur_invariant = !_short_loop_optimizer->has_indexed_store(as_BasicType(cur->type())) && is_invariant(li->array()) && is_invariant(li->index());
+}
+if (cur_invariant) {
+// perform value numbering and mark instruction as loop-invariant
+_gvn->substitute(cur);
+if (cur->as_Constant() == NULL) {
+// ensure that code for non-constant instructions is always generated
+cur->pin();
+}
+// remove cur instruction from loop block and append it to block before loop
+Instruction* next = cur->next();
+Instruction* in = _insertion_point->next();
+_insertion_point = _insertion_point->set_next(cur);
+cur->set_next(in);
+//  Deoptimize on exception
+cur->set_flag(Instruction::DeoptimizeOnException, true);
+//  Clear exception handlers
+cur->set_exception_handlers(NULL);
+TRACE_VALUE_NUMBERING(tty->print_cr("Instruction %c%d is loop invariant", cur->type()->tchar(), cur->id()));
+if (cur->state_before() != NULL) {
+cur->set_state_before(_state->copy());
+}
+if (cur->exception_state() != NULL) {
+cur->set_exception_state(_state->copy());
+}
+cur = prev->set_next(next);
+} else {
+prev = cur;
+cur = cur->next();
+}
+}
+}
 bool ShortLoopOptimizer::process(BlockBegin* loop_header) {
 TRACE_VALUE_NUMBERING(tty->print_cr("** loop header block"));
 _too_complicated_loop = false;
 }
 // add predecessors to worklist
 for (int j = block->number_of_preds() - 1; j >= 0; j--) {
 BlockBegin* pred = block->pred_at(j);
+if (pred->is_set(BlockBegin::osr_entry_flag)) {
+return false;
+}
 ValueMap* pred_map = value_map_of(pred);
 if (pred_map != NULL) {
 current_map()->kill_map(pred_map);
 } else if (!_loop_blocks.contains(pred)) {
 return false;
 }
 }
 }
+bool optimistic = this->_gvn->compilation()->is_optimistic();
+if (UseLoopInvariantCodeMotion && optimistic) {
+LoopInvariantCodeMotion code_motion(this, _gvn, loop_header, &_loop_blocks);
+}
 TRACE_VALUE_NUMBERING(tty->print_cr("** loop successfully optimized"));
 return true;
 }
 GlobalValueNumbering::GlobalValueNumbering(IR* ir)
 : _current_map(NULL)
 , _value_maps(ir->linear_scan_order()->length(), NULL)
+, _compilation(ir->compilation())
 {
 TRACE_VALUE_NUMBERING(tty->print_cr("****** start of global value numbering"));
 ShortLoopOptimizer short_loop_optimizer(this);
-int subst_count = 0;
 BlockList* blocks = ir->linear_scan_order();
 int num_blocks = blocks->length();
 BlockBegin* start_block = blocks->at(0);
 assert(start_block == ir->start() && start_block->number_of_preds() == 0 && start_block->dominator() == NULL, "must be start block");
 assert(start_block->next()->as_Base() != NULL && start_block->next()->next() == NULL, "start block must not have instructions");
+// method parameters are not linked in instructions list, so process them separateley
+for_each_state_value(start_block->state(), value,
+assert(value->as_Local() != NULL, "only method parameters allowed");
+set_processed(value);
+);
 // initial, empty value map with nesting 0
 set_value_map_of(start_block, new ValueMap());
 for (int i = 1; i < num_blocks; i++) {
 BlockBegin* block = blocks->at(i);
 assert(value_map_of(dominator) != NULL, "value map of dominator must exist");
 // create new value map with increased nesting
 _current_map = new ValueMap(value_map_of(dominator));
-if (num_preds == 1) {
+if (num_preds == 1 && !block->is_set(BlockBegin::exception_entry_flag)) {
 assert(dominator == block->pred_at(0), "dominator must be equal to predecessor");
 // nothing to do here
 } else if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) {
 // block has incoming backward branches -> try to optimize short loops
 current_map()->kill_memory();
 }
 }
 }
-if (block->is_set(BlockBegin::exception_entry_flag)) {
+// phi functions are not linked in instructions list, so process them separateley
-current_map()->kill_exception();
+for_each_phi_fun(block, phi,
-}
+set_processed(phi);
+);
 TRACE_VALUE_NUMBERING(tty->print("value map before processing block: "); current_map()->print());
 // visit all instructions of this block
 for (Value instr = block->next(); instr != NULL; instr = instr->next()) {
-assert(!instr->has_subst(), "substitution already set");
 // check if instruction kills any values
 instr->visit(this);
+// perform actual value numbering
-if (instr->hash() != 0) {
+substitute(instr);
-Value f = current_map()->find_insert(instr);
-if (f != instr) {
-assert(!f->has_subst(), "can't have a substitution");
-instr->set_subst(f);
-subst_count++;
-}
-}
 }
 // remember value map for successors
 set_value_map_of(block, current_map());
 }
-if (subst_count != 0) {
+if (_has_substitutions) {
 SubstitutionResolver resolver(ir);
 }
 TRACE_VALUE_NUMBERING(tty->print("****** end of global value numbering. "); ValueMap::print_statistics());
 }
+void GlobalValueNumbering::substitute(Instruction* instr) {
+assert(!instr->has_subst(), "substitution already set");
+Value subst = current_map()->find_insert(instr);
+if (subst != instr) {
+assert(!subst->has_subst(), "can't have a substitution");
+TRACE_VALUE_NUMBERING(tty->print_cr("substitution for %d set to %d", instr->id(), subst->id()));
+instr->set_subst(subst);
+_has_substitutions = true;
+}
+set_processed(instr);
+}

Mercurial > hg > truffle

comparison src/share/vm/c1/c1_ValueMap.cpp @ 8860:46f6f063b272