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comparison src/share/vm/opto/gcm.cpp @ 14440:41b780b43b74

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8029015: PPC64 (part 216): opto: trap based null and range checks Summary: On PPC64 use tdi instruction that does a compare and raises SIGTRAP for NULL and range checks. Reviewed-by: kvn
author goetz
date Wed, 27 Nov 2013 16:16:21 -0800
parents 2b8e28fdf503
children abec000618bf
comparison
equal deleted inserted replaced
14439:50fdb38839eb 14440:41b780b43b74
1328 1328
1329 // Detect implicit-null-check opportunities. Basically, find NULL checks 1329 // Detect implicit-null-check opportunities. Basically, find NULL checks
1330 // with suitable memory ops nearby. Use the memory op to do the NULL check. 1330 // with suitable memory ops nearby. Use the memory op to do the NULL check.
1331 // I can generate a memory op if there is not one nearby. 1331 // I can generate a memory op if there is not one nearby.
1332 if (C->is_method_compilation()) { 1332 if (C->is_method_compilation()) {
1333 // Don't do it for natives, adapters, or runtime stubs
1334 int allowed_reasons = 0;
1335 // ...and don't do it when there have been too many traps, globally.
1336 for (int reason = (int)Deoptimization::Reason_none+1;
1337 reason < Compile::trapHistLength; reason++) {
1338 assert(reason < BitsPerInt, "recode bit map");
1339 if (!C->too_many_traps((Deoptimization::DeoptReason) reason))
1340 allowed_reasons |= nth_bit(reason);
1341 }
1342 // By reversing the loop direction we get a very minor gain on mpegaudio. 1333 // By reversing the loop direction we get a very minor gain on mpegaudio.
1343 // Feel free to revert to a forward loop for clarity. 1334 // Feel free to revert to a forward loop for clarity.
1344 // for( int i=0; i < (int)matcher._null_check_tests.size(); i+=2 ) { 1335 // for( int i=0; i < (int)matcher._null_check_tests.size(); i+=2 ) {
1345 for (int i = _matcher._null_check_tests.size() - 2; i >= 0; i -= 2) { 1336 for (int i = _matcher._null_check_tests.size() - 2; i >= 0; i -= 2) {
1346 Node* proj = _matcher._null_check_tests[i]; 1337 Node* proj = _matcher._null_check_tests[i];
1347 Node* val = _matcher._null_check_tests[i + 1]; 1338 Node* val = _matcher._null_check_tests[i + 1];
1348 Block* block = get_block_for_node(proj); 1339 Block* block = get_block_for_node(proj);
1349 implicit_null_check(block, proj, val, allowed_reasons); 1340 implicit_null_check(block, proj, val, C->allowed_deopt_reasons());
1350 // The implicit_null_check will only perform the transformation 1341 // The implicit_null_check will only perform the transformation
1351 // if the null branch is truly uncommon, *and* it leads to an 1342 // if the null branch is truly uncommon, *and* it leads to an
1352 // uncommon trap. Combined with the too_many_traps guards 1343 // uncommon trap. Combined with the too_many_traps guards
1353 // above, this prevents SEGV storms reported in 6366351, 1344 // above, this prevents SEGV storms reported in 6366351,
1354 // by recompiling offending methods without this optimization. 1345 // by recompiling offending methods without this optimization.