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7054211: No loop unrolling done in jdk7b144 for a test update() while loop

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Restore unrolling code for CaffeineMark.

Reviewed-by: never
This commit is contained in:
Vladimir Kozlov 2011-09-07 12:58:42 -07:00
parent 48ecf5dfe4
commit 61068411fa
1 changed files with 5 additions and 1 deletions
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6
hotspot/src/share/vm/opto/loopTransform.cpp
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@ -709,10 +709,13 @@ bool IdealLoopTree::policy_unroll( PhaseIdealLoop *phase ) const {
// Adjust body_size to determine if we unroll or not
uint body_size = _body.size();
// Key test to unroll loop in CRC32 java code
int xors_in_loop = 0;
// Also count ModL, DivL and MulL which expand mightly
for (uint k = 0; k < _body.size(); k++) {
Node* n = _body.at(k);
switch (n->Opcode()) {
case Op_XorI: xors_in_loop++; break; // CRC32 java code
case Op_ModL: body_size += 30; break;
case Op_DivL: body_size += 30; break;
case Op_MulL: body_size += 10; break;
@ -729,7 +732,8 @@ bool IdealLoopTree::policy_unroll( PhaseIdealLoop *phase ) const {
// Check for being too big
if (body_size > (uint)LoopUnrollLimit) {
// Normal case: loop too big
if (xors_in_loop >= 4 && body_size < (uint)LoopUnrollLimit*4) return true;
// Normal case: loop too big
return false;
}