# HG changeset patch
# User rasbold
# Date 1222296996 25200
# Node ID 5f85534046c2c8d8129a5b198099fb41840bdd32
# Parent  36ccc817fca4894becf4c75a51324d4a77790890
6750588: assert(lrg._area >= 0,"negative spill area") running NSK stmp0101 test
Summary: handle NaN costs more carefully
Reviewed-by: kvn, never

diff -r 36ccc817fca4 -r 5f85534046c2 src/share/vm/opto/ifg.cpp
--- a/src/share/vm/opto/ifg.cpp	Tue Sep 23 12:29:06 2008 -0700
+++ b/src/share/vm/opto/ifg.cpp	Wed Sep 24 15:56:36 2008 -0700
@@ -485,8 +485,9 @@
     // Liveout things are presumed live for the whole block.  We accumulate
     // 'area' accordingly.  If they get killed in the block, we'll subtract
     // the unused part of the block from the area.
-    double cost = b->_freq * double(last_inst-last_phi);
-    assert( cost >= 0, "negative spill cost" );
+    int inst_count = last_inst - last_phi;
+    double cost = (inst_count <= 0) ? 0.0 : b->_freq * double(inst_count);
+    assert(!(cost < 0.0), "negative spill cost" );
     IndexSetIterator elements(&liveout);
     uint lidx;
     while ((lidx = elements.next()) != 0) {
@@ -590,7 +591,7 @@
         } else {                // Else it is live
           // A DEF also ends 'area' partway through the block.
           lrgs(r)._area -= cost;
-          assert( lrgs(r)._area >= 0, "negative spill area" );
+          assert(!(lrgs(r)._area < 0.0), "negative spill area" );
 
           // Insure high score for immediate-use spill copies so they get a color
           if( n->is_SpillCopy()
@@ -703,8 +704,9 @@
 
       } // End of if normal register-allocated value
 
-      cost -= b->_freq;         // Area remaining in the block
-      if( cost < 0.0 ) cost = 0.0;  // Cost goes negative in the Phi area
+      // Area remaining in the block
+      inst_count--;
+      cost = (inst_count <= 0) ? 0.0 : b->_freq * double(inst_count);
 
       // Make all inputs live
       if( !n->is_Phi() ) {      // Phi function uses come from prior block
@@ -751,7 +753,7 @@
             assert( pressure[0] == count_int_pressure  (&liveout), "" );
             assert( pressure[1] == count_float_pressure(&liveout), "" );
           }
-          assert( lrg._area >= 0, "negative spill area" );
+          assert(!(lrg._area < 0.0), "negative spill area" );
         }
       }
     } // End of reverse pass over all instructions in block