--- old/src/cpu/x86/vm/c1_LinearScan_x86.cpp	Tue Aug 25 15:22:49 2009
+++ new/src/cpu/x86/vm/c1_LinearScan_x86.cpp	Tue Aug 25 15:22:49 2009
@@ -764,8 +764,6 @@
       break;
     }
 
-    case lir_log:
-    case lir_log10:
     case lir_abs:
     case lir_sqrt: {
       // Right argument appears to be unused
@@ -784,6 +782,30 @@
       op2->set_fpu_stack_size(sim()->stack_size());
       break;
     }
+
+    case lir_log:
+    case lir_log10: {
+      // log and log10 needs one temporary fpu stack slot, so there is ontemporary
+      // registers stored in temp of the operation.
+      // the stack allocator must guarantee that the stack slots are really free,
+      // otherwise there might be a stack overflow.
+      assert(right->is_illegal(), "must be");
+      assert(left->is_fpu_register(), "must be");
+      assert(res->is_fpu_register(), "must be");
+      assert(op2->tmp_opr()->is_fpu_register(), "must be");
+
+      insert_free_if_dead(op2->tmp_opr());
+      insert_free_if_dead(res, left);
+      insert_exchange(left);
+      do_rename(left, res);
+
+      new_left = to_fpu_stack_top(res);
+      new_res = new_left;
+
+      op2->set_fpu_stack_size(sim()->stack_size());
+      assert(sim()->stack_size() <= 7, "at least one stack slot must be free");
+      break;
+    }
 
 
     case lir_tan: