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comparison src/share/vm/opto/block.cpp @ 12171:4b078f877b56

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8023988: Move local scheduling of nodes to the CFG creation and code motion phase (PhaseCFG) Summary: Moved local scheduling code from class Block to class PhaseCFG Reviewed-by: kvn, roland
author adlertz
date Sun, 01 Sep 2013 19:21:05 +0200
parents 650868c062a9
children de6a9e811145 044b28168e20
comparison
equal deleted inserted replaced
12169:29aa8936f03c 12171:4b078f877b56
207 return op == Op_Halt; 207 return op == Op_Halt;
208 } 208 }
209 209
210 // True if block is low enough frequency or guarded by a test which 210 // True if block is low enough frequency or guarded by a test which
211 // mostly does not go here. 211 // mostly does not go here.
212 bool Block::is_uncommon(PhaseCFG* cfg) const { 212 bool PhaseCFG::is_uncommon(const Block* block) {
213 // Initial blocks must never be moved, so are never uncommon. 213 // Initial blocks must never be moved, so are never uncommon.
214 if (head()->is_Root() || head()->is_Start()) return false; 214 if (block->head()->is_Root() || block->head()->is_Start()) return false;
215 215
216 // Check for way-low freq 216 // Check for way-low freq
217 if( _freq < BLOCK_FREQUENCY(0.00001f) ) return true; 217 if(block->_freq < BLOCK_FREQUENCY(0.00001f) ) return true;
218 218
219 // Look for code shape indicating uncommon_trap or slow path 219 // Look for code shape indicating uncommon_trap or slow path
220 if (has_uncommon_code()) return true; 220 if (block->has_uncommon_code()) return true;
221 221
222 const float epsilon = 0.05f; 222 const float epsilon = 0.05f;
223 const float guard_factor = PROB_UNLIKELY_MAG(4) / (1.f - epsilon); 223 const float guard_factor = PROB_UNLIKELY_MAG(4) / (1.f - epsilon);
224 uint uncommon_preds = 0; 224 uint uncommon_preds = 0;
225 uint freq_preds = 0; 225 uint freq_preds = 0;
226 uint uncommon_for_freq_preds = 0; 226 uint uncommon_for_freq_preds = 0;
227 227
228 for( uint i=1; i<num_preds(); i++ ) { 228 for( uint i=1; i< block->num_preds(); i++ ) {
229 Block* guard = cfg->get_block_for_node(pred(i)); 229 Block* guard = get_block_for_node(block->pred(i));
230 // Check to see if this block follows its guard 1 time out of 10000 230 // Check to see if this block follows its guard 1 time out of 10000
231 // or less. 231 // or less.
232 // 232 //
233 // See list of magnitude-4 unlikely probabilities in cfgnode.hpp which 233 // See list of magnitude-4 unlikely probabilities in cfgnode.hpp which
234 // we intend to be "uncommon", such as slow-path TLE allocation, 234 // we intend to be "uncommon", such as slow-path TLE allocation,
242 // The next check is (guard->_freq < 1.e-5 * 9500.). 242 // The next check is (guard->_freq < 1.e-5 * 9500.).
243 if(guard->_freq*BLOCK_FREQUENCY(guard_factor) < BLOCK_FREQUENCY(0.00001f)) { 243 if(guard->_freq*BLOCK_FREQUENCY(guard_factor) < BLOCK_FREQUENCY(0.00001f)) {
244 uncommon_preds++; 244 uncommon_preds++;
245 } else { 245 } else {
246 freq_preds++; 246 freq_preds++;
247 if( _freq < guard->_freq * guard_factor ) { 247 if(block->_freq < guard->_freq * guard_factor ) {
248 uncommon_for_freq_preds++; 248 uncommon_for_freq_preds++;
249 } 249 }
250 } 250 }
251 } 251 }
252 if( num_preds() > 1 && 252 if( block->num_preds() > 1 &&
253 // The block is uncommon if all preds are uncommon or 253 // The block is uncommon if all preds are uncommon or
254 (uncommon_preds == (num_preds()-1) || 254 (uncommon_preds == (block->num_preds()-1) ||
255 // it is uncommon for all frequent preds. 255 // it is uncommon for all frequent preds.
256 uncommon_for_freq_preds == freq_preds) ) { 256 uncommon_for_freq_preds == freq_preds) ) {
257 return true; 257 return true;
258 } 258 }
259 return false; 259 return false;
667 convert_NeverBranch_to_Goto(block); 667 convert_NeverBranch_to_Goto(block);
668 } 668 }
669 669
670 // Look for uncommon blocks and move to end. 670 // Look for uncommon blocks and move to end.
671 if (!C->do_freq_based_layout()) { 671 if (!C->do_freq_based_layout()) {
672 if (block->is_uncommon(this)) { 672 if (is_uncommon(block)) {
673 move_to_end(block, i); 673 move_to_end(block, i);
674 last--; // No longer check for being uncommon! 674 last--; // No longer check for being uncommon!
675 if (no_flip_branch(block)) { // Fall-thru case must follow? 675 if (no_flip_branch(block)) { // Fall-thru case must follow?
676 // Find the fall-thru block 676 // Find the fall-thru block
677 block = get_block(i); 677 block = get_block(i);