From 07537703cc96d8eb5a78b7186d60ccab31eba2ad Mon Sep 17 00:00:00 2001
From: Roland Westrelin <roland@openjdk.org>
Date: Thu, 4 Dec 2014 14:34:11 +0100
Subject: [PATCH] 8048170: Test
 closed/java/text/Normalizer/ConformanceTest.java failed

PhaseIdealLoop::split_if_with_blocks_post() shoulnd't reorder range checks adjusted by range check smearing

Reviewed-by: kvn, jrose
---
 hotspot/src/share/vm/opto/loopopts.cpp        | 17 +++--
 .../TestRangeCheckSmearingLoopOpts.java       | 76 +++++++++++++++++++
 2 files changed, 87 insertions(+), 6 deletions(-)
 create mode 100644 hotspot/test/compiler/rangechecks/TestRangeCheckSmearingLoopOpts.java

diff --git a/hotspot/src/share/vm/opto/loopopts.cpp b/hotspot/src/share/vm/opto/loopopts.cpp
index bfa483c0181..e00a47dbfda 100644
--- a/hotspot/src/share/vm/opto/loopopts.cpp
+++ b/hotspot/src/share/vm/opto/loopopts.cpp
@@ -241,8 +241,13 @@ void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff, bool flip, bool exc
   ProjNode* dp_proj  = dp->as_Proj();
   ProjNode* unc_proj = iff->as_If()->proj_out(1 - dp_proj->_con)->as_Proj();
   if (exclude_loop_predicate &&
-      unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate))
+      (unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate) ||
+       unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_range_check))) {
+    // If this is a range check (IfNode::is_range_check), do not
+    // reorder because Compile::allow_range_check_smearing might have
+    // changed the check.
     return; // Let IGVN transformation change control dependence.
+  }
 
   IdealLoopTree *old_loop = get_loop(dp);
 
@@ -898,23 +903,23 @@ void PhaseIdealLoop::split_if_with_blocks_post( Node *n ) {
   int n_op = n->Opcode();
 
   // Check for an IF being dominated by another IF same test
-  if( n_op == Op_If ) {
+  if (n_op == Op_If) {
     Node *bol = n->in(1);
     uint max = bol->outcnt();
     // Check for same test used more than once?
-    if( n_op == Op_If && max > 1 && bol->is_Bool() ) {
+    if (max > 1 && bol->is_Bool()) {
       // Search up IDOMs to see if this IF is dominated.
       Node *cutoff = get_ctrl(bol);
 
       // Now search up IDOMs till cutoff, looking for a dominating test
       Node *prevdom = n;
       Node *dom = idom(prevdom);
-      while( dom != cutoff ) {
-        if( dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom ) {
+      while (dom != cutoff) {
+        if (dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom) {
           // Replace the dominated test with an obvious true or false.
           // Place it on the IGVN worklist for later cleanup.
           C->set_major_progress();
-          dominated_by( prevdom, n, false, true );
+          dominated_by(prevdom, n, false, true);
 #ifndef PRODUCT
           if( VerifyLoopOptimizations ) verify();
 #endif
diff --git a/hotspot/test/compiler/rangechecks/TestRangeCheckSmearingLoopOpts.java b/hotspot/test/compiler/rangechecks/TestRangeCheckSmearingLoopOpts.java
new file mode 100644
index 00000000000..699754a8e8c
--- /dev/null
+++ b/hotspot/test/compiler/rangechecks/TestRangeCheckSmearingLoopOpts.java
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8048170
+ * @summary Following range check smearing, range check cannot be replaced by dominating identical test.
+ * @run main/othervm -XX:-BackgroundCompilation -XX:-UseOnStackReplacement TestRangeCheckSmearingLoopOpts
+ *
+ */
+public class TestRangeCheckSmearingLoopOpts {
+
+    static int dummy;
+
+    static int m1(int[] array, int i) {
+        for (;;) {
+            for (;;) {
+                if (array[i] < 0) { // range check (i+0) dominates equivalent check below
+                    break;
+                }
+                i++;
+            }
+
+            // A control flow that stops IfNode::up_one_dom()
+            if ((i % 2)== 0) {
+                if ((array[i] % 2) == 0) {
+                    dummy = i;
+                }
+            }
+
+            // IfNode::Ideal will rewrite some range checks if Compile::allow_range_check_smearing
+            if (array[i-1] == 9) {    // range check (i-1) unchanged
+                int res = array[i-3]; // range check (i-3) unchanged
+                res += array[i];      // range check (i+0) unchanged
+                res += array[i-2];    // removed redundant range check
+                // the previous access might be hoisted by
+                // PhaseIdealLoop::split_if_with_blocks_post because
+                // it appears to have the same guard, but it also
+                // depends on the previous guards
+                return res;
+            }
+            i++;
+        }
+    }
+
+    static public void main(String[] args) {
+        int[] array = { 0, 1, 2, -3, 4, 5, -2, 7, 8, 9, -1 };
+        for (int i = 0; i < 20000; i++) {
+            m1(array, 0);
+        }
+        array[0] = -1;
+        try {
+            m1(array, 0);
+        } catch(ArrayIndexOutOfBoundsException aioobe) {}
+    }
+}