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6667588: Don't generate duplicated CMP for float/double values

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Float CMove generation add duplicated CMPF if there are more then one Move depending on the condition.

Reviewed-by: jrose, never, rasbold
This commit is contained in:
Vladimir Kozlov 2008-02-29 19:07:15 -08:00
parent 7ec44373b5
commit 09d7f4bbcf
1 changed files with 8 additions and 0 deletions
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8
hotspot/src/share/vm/opto/loopopts.cpp
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@ -435,9 +435,11 @@ Node *PhaseIdealLoop::conditional_move( Node *region ) {
// Check profitability // Check profitability
int cost = 0; int cost = 0;
int phis = 0;
for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
Node *out = region->fast_out(i); Node *out = region->fast_out(i);
if( !out->is_Phi() ) continue; // Ignore other control edges, etc if( !out->is_Phi() ) continue; // Ignore other control edges, etc
phis++;
PhiNode* phi = out->as_Phi(); PhiNode* phi = out->as_Phi();
switch (phi->type()->basic_type()) { switch (phi->type()->basic_type()) {
case T_LONG: case T_LONG:
@ -489,6 +491,12 @@ Node *PhaseIdealLoop::conditional_move( Node *region ) {
} }
} }
if( cost >= ConditionalMoveLimit ) return NULL; // Too much goo if( cost >= ConditionalMoveLimit ) return NULL; // Too much goo
Node* bol = iff->in(1);
assert( bol->Opcode() == Op_Bool, "" );
int cmp_op = bol->in(1)->Opcode();
// It is expensive to generate flags from a float compare.
// Avoid duplicated float compare.
if( phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL;
// -------------- // --------------
// Now replace all Phis with CMOV's // Now replace all Phis with CMOV's