6659207: access violation in CompilerThread0

Summary: split_thru_phi produces top on a non-dead path
Reviewed-by: kvn, rasbold, sgoldman

src/share/vm/opto/loopopts.cpp

@@ -29,6 +29,11 @@
 //------------------------------split_thru_phi---------------------------------
 // Split Node 'n' through merge point if there is enough win.
 Node *PhaseIdealLoop::split_thru_phi( Node *n, Node *region, int policy ) {
+  if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) {
+    // ConvI2L may have type information on it which is unsafe to push up
+    // so disable this for now
+    return NULL;
+  }
   int wins = 0;
   assert( !n->is_CFG(), "" );
   assert( region->is_Region(), "" );

test/compiler/6659207/Test.java

+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ */
+
+/*
+ * @test
+ * @bug 6659207
+ * @summary access violation in CompilerThread0
+ */
+
+public class Test {
+    static int[] array = new int[12];
+
+    static int index(int i) {
+        if (i == 0) return 0;
+        for (int n = 0; n < array.length; n++)
+            if (i < array[n]) return n;
+        return -1;
+    }
+
+    static int test(int i) {
+        int result = 0;
+        i = index(i);
+        if (i >= 0)
+            if (array[i] != 0)
+                result++;
+
+        if (i != -1)
+            array[i]++;
+
+        return result;
+    }
+
+    public static void main(String[] args) {
+        int total = 0;
+        for (int i = 0; i < 100000; i++) {
+            total += test(10);
+        }
+        System.out.println(total);
+    }
+}