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changeset 35:e2ae28d2ce91

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6667588: Don't generate duplicated CMP for float/double values Summary: float CMove generation add duplicated CMPF if there are more then one Move depending on the condition. Reviewed-by: jrose, never, rasbold
author kvn
date Fri, 29 Feb 2008 19:07:15 -0800
parents 545c277a3ecf
children f34d9da7acb2
files src/share/vm/opto/loopopts.cpp
diffstat 1 files changed, 8 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- a/src/share/vm/opto/loopopts.cpp	Fri Feb 29 11:22:27 2008 -0800
+++ b/src/share/vm/opto/loopopts.cpp	Fri Feb 29 19:07:15 2008 -0800
@@ -435,9 +435,11 @@
 
   // Check profitability
   int cost = 0;
+  int phis = 0;
   for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
     Node *out = region->fast_out(i);
     if( !out->is_Phi() ) continue; // Ignore other control edges, etc
+    phis++;
     PhiNode* phi = out->as_Phi();
     switch (phi->type()->basic_type()) {
     case T_LONG:
@@ -489,6 +491,12 @@
     }
   }
   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