# HG changeset patch
# User Doug Simon <doug.simon@oracle.com>
# Date 1371484519 -7200
# Node ID abb9d3a2602570a43f0f778c92ec5aa94f16b35d
# Parent  529570e20afffc0f5d790922b148570d36c57d8d
an instanceof instruction lowers to a deoptimize-on-hint-miss snippet only if its profile indicates a miss (of a hint type) occurs an order of magnitude less than the compilation threshold

diff -r 529570e20aff -r abb9d3a26025 graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/HotSpotVMConfig.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/HotSpotVMConfig.java	Mon Jun 17 14:53:37 2013 +0200
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/HotSpotVMConfig.java	Mon Jun 17 17:55:19 2013 +0200
@@ -38,6 +38,7 @@
     public int codeEntryAlignment;
     public boolean verifyOops;
     public boolean ciTime;
+    public int compileThreshold;
     public boolean compileTheWorld;
     public int compileTheWorldStartAt;
     public int compileTheWorldStopAt;
diff -r 529570e20aff -r abb9d3a26025 graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/InstanceOfSnippets.java
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/InstanceOfSnippets.java	Mon Jun 17 14:53:37 2013 +0200
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/InstanceOfSnippets.java	Mon Jun 17 17:55:19 2013 +0200
@@ -59,10 +59,23 @@
 public class InstanceOfSnippets implements Snippets {
 
     /**
+     * Gets the minimum required probability of a profiled instanceof hitting one the profiled types
+     * for use of the {@linkplain #instanceofWithProfile deoptimizing} snippet. The value is
+     * computed to be an order of magnitude greater than the configured compilation threshold. For
+     * example, if a method is compiled after being interpreted 10000 times, the deoptimizing
+     * snippet will only be used for an instanceof if its profile indicates that less than 1 in
+     * 100000 executions are for an object whose type is not one of the top N profiled types (where
+     * {@code N == } {@link GraalOptions#InstanceOfMaxHints}).
+     */
+    public static double hintHitProbabilityThresholdForDeoptimizingSnippet() {
+        return 1.0D - (1.0D / (graalRuntime().getConfig().compileThreshold * 10));
+    }
+
+    /**
      * A test against a set of hints derived from a profile with very close to 100% precise coverage
      * of seen types. This snippet deoptimizes on hint miss paths.
      * 
-     * @see GraalOptions#InstanceOfFullCoverageSpeculationThreshold
+     * @see #hintHitProbabilityThresholdForDeoptimizingSnippet()
      */
     @Snippet
     public static Object instanceofWithProfile(Object object, @VarargsParameter Word[] hints, @VarargsParameter boolean[] hintIsPositive, Object trueValue, Object falseValue,
@@ -196,7 +209,8 @@
                 ConstantNode hub = ConstantNode.forConstant(type.klass(), runtime, instanceOf.graph());
 
                 Arguments args;
-                if (hintInfo.hintHitProbability >= InstanceOfFullCoverageSpeculationThreshold.getValue()) {
+
+                if (hintInfo.hintHitProbability >= hintHitProbabilityThresholdForDeoptimizingSnippet()) {
                     Hints hints = createHints(hintInfo, runtime, false, hub.graph());
                     args = new Arguments(instanceofWithProfile);
                     args.add("object", object);
@@ -222,7 +236,7 @@
                 args.add("trueValue", replacer.trueValue);
                 args.add("falseValue", replacer.falseValue);
                 args.addConst("checkNull", !object.stamp().nonNull());
-                if (hintInfo.hintHitProbability >= InstanceOfFullCoverageSpeculationThreshold.getValue()) {
+                if (hintInfo.hintHitProbability >= hintHitProbabilityThresholdForDeoptimizingSnippet()) {
                     args.addConst("nullSeen", hintInfo.profile.getNullSeen() != TriState.FALSE);
                 }
                 return args;
diff -r 529570e20aff -r abb9d3a26025 graal/com.oracle.graal.phases/src/com/oracle/graal/phases/GraalOptions.java
--- a/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/GraalOptions.java	Mon Jun 17 14:53:37 2013 +0200
+++ b/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/GraalOptions.java	Mon Jun 17 17:55:19 2013 +0200
@@ -343,12 +343,4 @@
      */
     @Option(help = "")
     public static final OptionValue<Integer> InstanceOfMaxHints = new OptionValue<>(2);
-
-    /**
-     * If the probability that an instanceof will hit one the profiled types (up to {@link #InstanceOfMaxHints})
-     * is above this value, the compiled instanceof will deoptimize if all hints are missed.
-     */
-    @Option(help = "")
-    public static final OptionValue<Double> InstanceOfFullCoverageSpeculationThreshold = new OptionValue<>(0.998);
-
 }
diff -r 529570e20aff -r abb9d3a26025 src/share/vm/graal/graalCompilerToVM.cpp
--- a/src/share/vm/graal/graalCompilerToVM.cpp	Mon Jun 17 14:53:37 2013 +0200
+++ b/src/share/vm/graal/graalCompilerToVM.cpp	Mon Jun 17 17:55:19 2013 +0200
@@ -668,6 +668,7 @@
   set_boolean("cAssertions", DEBUG_ONLY(true) NOT_DEBUG(false));
   set_boolean("verifyOops", VerifyOops);
   set_boolean("ciTime", CITime);
+  set_int("compileThreshold", CompileThreshold);
   set_boolean("compileTheWorld", CompileTheWorld);
   set_int("compileTheWorldStartAt", CompileTheWorldStartAt);
   set_int("compileTheWorldStopAt", CompileTheWorldStopAt);