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src/share/vm/c1/c1_Canonicalizer.cpp

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rev 9067 : 8139040: Fix initializations before ShouldNotReachHere()


 622   return false;
 623 }
 624 
 625 static bool is_safepoint(BlockEnd* x, BlockBegin* sux) {
 626   // An Instruction with multiple successors, x, is replaced by a Goto
 627   // to a single successor, sux. Is a safepoint check needed = was the
 628   // instruction being replaced a safepoint and the single remaining
 629   // successor a back branch?
 630   return x->is_safepoint() && (sux->bci() < x->state_before()->bci());
 631 }
 632 
 633 void Canonicalizer::do_If(If* x) {
 634   // move const to right
 635   if (x->x()->type()->is_constant()) x->swap_operands();
 636   // simplify
 637   const Value l = x->x(); ValueType* lt = l->type();
 638   const Value r = x->y(); ValueType* rt = r->type();
 639 
 640   if (l == r && !lt->is_float_kind()) {
 641     // pattern: If (a cond a) => simplify to Goto
 642     BlockBegin* sux;
 643     switch (x->cond()) {
 644     case If::eql: sux = x->sux_for(true);  break;
 645     case If::neq: sux = x->sux_for(false); break;
 646     case If::lss: sux = x->sux_for(false); break;
 647     case If::leq: sux = x->sux_for(true);  break;
 648     case If::gtr: sux = x->sux_for(false); break;
 649     case If::geq: sux = x->sux_for(true);  break;
 650     }
 651     // If is a safepoint then the debug information should come from the state_before of the If.
 652     set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
 653     return;
 654   }
 655 
 656   if (lt->is_constant() && rt->is_constant()) {
 657     if (x->x()->as_Constant() != NULL) {
 658       // pattern: If (lc cond rc) => simplify to: Goto
 659       BlockBegin* sux = x->x()->as_Constant()->compare(x->cond(), x->y(),
 660                                                        x->sux_for(true),
 661                                                        x->sux_for(false));
 662       if (sux != NULL) {


 667   } else if (rt->as_IntConstant() != NULL) {
 668     // pattern: If (l cond rc) => investigate further
 669     const jint rc = rt->as_IntConstant()->value();
 670     if (l->as_CompareOp() != NULL) {
 671       // pattern: If ((a cmp b) cond rc) => simplify to: If (x cond y) or: Goto
 672       CompareOp* cmp = l->as_CompareOp();
 673       bool unordered_is_less = cmp->op() == Bytecodes::_fcmpl || cmp->op() == Bytecodes::_dcmpl;
 674       BlockBegin* lss_sux = x->sux_for(is_true(-1, x->cond(), rc)); // successor for a < b
 675       BlockBegin* eql_sux = x->sux_for(is_true( 0, x->cond(), rc)); // successor for a = b
 676       BlockBegin* gtr_sux = x->sux_for(is_true(+1, x->cond(), rc)); // successor for a > b
 677       BlockBegin* nan_sux = unordered_is_less ? lss_sux : gtr_sux ; // successor for unordered
 678       // Note: At this point all successors (lss_sux, eql_sux, gtr_sux, nan_sux) are
 679       //       equal to x->tsux() or x->fsux(). Furthermore, nan_sux equals either
 680       //       lss_sux or gtr_sux.
 681       if (lss_sux == eql_sux && eql_sux == gtr_sux) {
 682         // all successors identical => simplify to: Goto
 683         set_canonical(new Goto(lss_sux, x->state_before(), x->is_safepoint()));
 684       } else {
 685         // two successors differ and two successors are the same => simplify to: If (x cmp y)
 686         // determine new condition & successors
 687         If::Condition cond;
 688         BlockBegin* tsux = NULL;
 689         BlockBegin* fsux = NULL;
 690              if (lss_sux == eql_sux) { cond = If::leq; tsux = lss_sux; fsux = gtr_sux; }
 691         else if (lss_sux == gtr_sux) { cond = If::neq; tsux = lss_sux; fsux = eql_sux; }
 692         else if (eql_sux == gtr_sux) { cond = If::geq; tsux = eql_sux; fsux = lss_sux; }
 693         else                         { ShouldNotReachHere();                           }
 694         If* canon = new If(cmp->x(), cond, nan_sux == tsux, cmp->y(), tsux, fsux, cmp->state_before(), x->is_safepoint());
 695         if (cmp->x() == cmp->y()) {
 696           do_If(canon);
 697         } else {
 698           if (compilation()->profile_branches()) {
 699             // TODO: If profiling, leave floating point comparisons unoptimized.
 700             // We currently do not support profiling of the unordered case.
 701             switch(cmp->op()) {
 702               case Bytecodes::_fcmpl: case Bytecodes::_fcmpg:
 703               case Bytecodes::_dcmpl: case Bytecodes::_dcmpg:
 704                 set_canonical(x);
 705                 return;
 706             }
 707           }




 622   return false;
 623 }
 624 
 625 static bool is_safepoint(BlockEnd* x, BlockBegin* sux) {
 626   // An Instruction with multiple successors, x, is replaced by a Goto
 627   // to a single successor, sux. Is a safepoint check needed = was the
 628   // instruction being replaced a safepoint and the single remaining
 629   // successor a back branch?
 630   return x->is_safepoint() && (sux->bci() < x->state_before()->bci());
 631 }
 632 
 633 void Canonicalizer::do_If(If* x) {
 634   // move const to right
 635   if (x->x()->type()->is_constant()) x->swap_operands();
 636   // simplify
 637   const Value l = x->x(); ValueType* lt = l->type();
 638   const Value r = x->y(); ValueType* rt = r->type();
 639 
 640   if (l == r && !lt->is_float_kind()) {
 641     // pattern: If (a cond a) => simplify to Goto
 642     BlockBegin* sux = NULL;
 643     switch (x->cond()) {
 644     case If::eql: sux = x->sux_for(true);  break;
 645     case If::neq: sux = x->sux_for(false); break;
 646     case If::lss: sux = x->sux_for(false); break;
 647     case If::leq: sux = x->sux_for(true);  break;
 648     case If::gtr: sux = x->sux_for(false); break;
 649     case If::geq: sux = x->sux_for(true);  break;
 650     }
 651     // If is a safepoint then the debug information should come from the state_before of the If.
 652     set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
 653     return;
 654   }
 655 
 656   if (lt->is_constant() && rt->is_constant()) {
 657     if (x->x()->as_Constant() != NULL) {
 658       // pattern: If (lc cond rc) => simplify to: Goto
 659       BlockBegin* sux = x->x()->as_Constant()->compare(x->cond(), x->y(),
 660                                                        x->sux_for(true),
 661                                                        x->sux_for(false));
 662       if (sux != NULL) {


 667   } else if (rt->as_IntConstant() != NULL) {
 668     // pattern: If (l cond rc) => investigate further
 669     const jint rc = rt->as_IntConstant()->value();
 670     if (l->as_CompareOp() != NULL) {
 671       // pattern: If ((a cmp b) cond rc) => simplify to: If (x cond y) or: Goto
 672       CompareOp* cmp = l->as_CompareOp();
 673       bool unordered_is_less = cmp->op() == Bytecodes::_fcmpl || cmp->op() == Bytecodes::_dcmpl;
 674       BlockBegin* lss_sux = x->sux_for(is_true(-1, x->cond(), rc)); // successor for a < b
 675       BlockBegin* eql_sux = x->sux_for(is_true( 0, x->cond(), rc)); // successor for a = b
 676       BlockBegin* gtr_sux = x->sux_for(is_true(+1, x->cond(), rc)); // successor for a > b
 677       BlockBegin* nan_sux = unordered_is_less ? lss_sux : gtr_sux ; // successor for unordered
 678       // Note: At this point all successors (lss_sux, eql_sux, gtr_sux, nan_sux) are
 679       //       equal to x->tsux() or x->fsux(). Furthermore, nan_sux equals either
 680       //       lss_sux or gtr_sux.
 681       if (lss_sux == eql_sux && eql_sux == gtr_sux) {
 682         // all successors identical => simplify to: Goto
 683         set_canonical(new Goto(lss_sux, x->state_before(), x->is_safepoint()));
 684       } else {
 685         // two successors differ and two successors are the same => simplify to: If (x cmp y)
 686         // determine new condition & successors
 687         If::Condition cond = If::eql;
 688         BlockBegin* tsux = NULL;
 689         BlockBegin* fsux = NULL;
 690              if (lss_sux == eql_sux) { cond = If::leq; tsux = lss_sux; fsux = gtr_sux; }
 691         else if (lss_sux == gtr_sux) { cond = If::neq; tsux = lss_sux; fsux = eql_sux; }
 692         else if (eql_sux == gtr_sux) { cond = If::geq; tsux = eql_sux; fsux = lss_sux; }
 693         else                         { ShouldNotReachHere();                           }
 694         If* canon = new If(cmp->x(), cond, nan_sux == tsux, cmp->y(), tsux, fsux, cmp->state_before(), x->is_safepoint());
 695         if (cmp->x() == cmp->y()) {
 696           do_If(canon);
 697         } else {
 698           if (compilation()->profile_branches()) {
 699             // TODO: If profiling, leave floating point comparisons unoptimized.
 700             // We currently do not support profiling of the unordered case.
 701             switch(cmp->op()) {
 702               case Bytecodes::_fcmpl: case Bytecodes::_fcmpg:
 703               case Bytecodes::_dcmpl: case Bytecodes::_dcmpg:
 704                 set_canonical(x);
 705                 return;
 706             }
 707           }


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