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comparison src/share/vm/opto/loopTransform.cpp @ 3930:da6a29fb0da5

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7054211: No loop unrolling done in jdk7b144 for a test update() while loop Summary: restore unrolling code for CaffeineMark. Reviewed-by: never
author kvn
date Wed, 07 Sep 2011 12:58:42 -0700
parents 6987871cfb9b
children 5e990493719e
comparison
equal deleted inserted replaced
3909:c2d3caa64b3e 3930:da6a29fb0da5
707 stride_con < 0 && ((limit_type->_lo - stride_con) <= limit_type->_lo)) 707 stride_con < 0 && ((limit_type->_lo - stride_con) <= limit_type->_lo))
708 return false; // overflow 708 return false; // overflow
709 709
710 // Adjust body_size to determine if we unroll or not 710 // Adjust body_size to determine if we unroll or not
711 uint body_size = _body.size(); 711 uint body_size = _body.size();
712 // Key test to unroll loop in CRC32 java code
713 int xors_in_loop = 0;
712 // Also count ModL, DivL and MulL which expand mightly 714 // Also count ModL, DivL and MulL which expand mightly
713 for (uint k = 0; k < _body.size(); k++) { 715 for (uint k = 0; k < _body.size(); k++) {
714 Node* n = _body.at(k); 716 Node* n = _body.at(k);
715 switch (n->Opcode()) { 717 switch (n->Opcode()) {
718 case Op_XorI: xors_in_loop++; break; // CRC32 java code
716 case Op_ModL: body_size += 30; break; 719 case Op_ModL: body_size += 30; break;
717 case Op_DivL: body_size += 30; break; 720 case Op_DivL: body_size += 30; break;
718 case Op_MulL: body_size += 10; break; 721 case Op_MulL: body_size += 10; break;
719 case Op_StrComp: 722 case Op_StrComp:
720 case Op_StrEquals: 723 case Op_StrEquals:
727 } // switch 730 } // switch
728 } 731 }
729 732
730 // Check for being too big 733 // Check for being too big
731 if (body_size > (uint)LoopUnrollLimit) { 734 if (body_size > (uint)LoopUnrollLimit) {
732 // Normal case: loop too big 735 if (xors_in_loop >= 4 && body_size < (uint)LoopUnrollLimit*4) return true;
736 // Normal case: loop too big
733 return false; 737 return false;
734 } 738 }
735 739
736 // Unroll once! (Each trip will soon do double iterations) 740 // Unroll once! (Each trip will soon do double iterations)
737 return true; 741 return true;