--- a/hotspot/src/share/vm/opto/loopTransform.cpp	Wed Mar 30 07:47:19 2011 -0700
+++ b/hotspot/src/share/vm/opto/loopTransform.cpp	Wed Mar 30 12:08:49 2011 -0700
@@ -396,16 +396,16 @@
 // Return exact loop trip count, or 0 if not maximally unrolling
 bool IdealLoopTree::policy_maximally_unroll( PhaseIdealLoop *phase ) const {
   CountedLoopNode *cl = _head->as_CountedLoop();
-  assert( cl->is_normal_loop(), "" );
+  assert(cl->is_normal_loop(), "");
 
   Node *init_n = cl->init_trip();
   Node *limit_n = cl->limit();
 
   // Non-constant bounds
-  if( init_n   == NULL || !init_n->is_Con()  ||
+  if (init_n   == NULL || !init_n->is_Con()  ||
       limit_n  == NULL || !limit_n->is_Con() ||
       // protect against stride not being a constant
-      !cl->stride_is_con() ) {
+      !cl->stride_is_con()) {
     return false;
   }
   int init   = init_n->get_int();
@@ -428,7 +428,25 @@
   uint unroll_limit = (uint)LoopUnrollLimit * 4;
   assert( (intx)unroll_limit == LoopUnrollLimit * 4, "LoopUnrollLimit must fit in 32bits");
   cl->set_trip_count(trip_count);
-  if( trip_count <= unroll_limit && body_size <= unroll_limit ) {
+  if (trip_count > unroll_limit || body_size > unroll_limit) {
+    return false;
+  }
+
+  // Do not unroll a loop with String intrinsics code.
+  // String intrinsics are large and have loops.
+  for (uint k = 0; k < _body.size(); k++) {
+    Node* n = _body.at(k);
+    switch (n->Opcode()) {
+      case Op_StrComp:
+      case Op_StrEquals:
+      case Op_StrIndexOf:
+      case Op_AryEq: {
+        return false;
+      }
+    } // switch
+  }
+
+  if (body_size <= unroll_limit) {
     uint new_body_size = body_size * trip_count;
     if (new_body_size <= unroll_limit &&
         body_size == new_body_size / trip_count &&
@@ -448,13 +466,13 @@
 bool IdealLoopTree::policy_unroll( PhaseIdealLoop *phase ) const {
 
   CountedLoopNode *cl = _head->as_CountedLoop();
-  assert( cl->is_normal_loop() || cl->is_main_loop(), "" );
+  assert(cl->is_normal_loop() || cl->is_main_loop(), "");
 
   // protect against stride not being a constant
-  if( !cl->stride_is_con() ) return false;
+  if (!cl->stride_is_con()) return false;
 
   // protect against over-unrolling
-  if( cl->trip_count() <= 1 ) return false;
+  if (cl->trip_count() <= 1) return false;
 
   int future_unroll_ct = cl->unrolled_count() * 2;
 
@@ -485,21 +503,21 @@
   // Non-constant bounds.
   // Protect against over-unrolling when init or/and limit are not constant
   // (so that trip_count's init value is maxint) but iv range is known.
-  if( init_n   == NULL || !init_n->is_Con()  ||
-      limit_n  == NULL || !limit_n->is_Con() ) {
+  if (init_n   == NULL || !init_n->is_Con()  ||
+      limit_n  == NULL || !limit_n->is_Con()) {
     Node* phi = cl->phi();
-    if( phi != NULL ) {
+    if (phi != NULL) {
       assert(phi->is_Phi() && phi->in(0) == _head, "Counted loop should have iv phi.");
       const TypeInt* iv_type = phase->_igvn.type(phi)->is_int();
       int next_stride = cl->stride_con() * 2; // stride after this unroll
-      if( next_stride > 0 ) {
-        if( iv_type->_lo + next_stride <= iv_type->_lo || // overflow
-            iv_type->_lo + next_stride >  iv_type->_hi ) {
+      if (next_stride > 0) {
+        if (iv_type->_lo + next_stride <= iv_type->_lo || // overflow
+            iv_type->_lo + next_stride >  iv_type->_hi) {
           return false;  // over-unrolling
         }
-      } else if( next_stride < 0 ) {
-        if( iv_type->_hi + next_stride >= iv_type->_hi || // overflow
-            iv_type->_hi + next_stride <  iv_type->_lo ) {
+      } else if (next_stride < 0) {
+        if (iv_type->_hi + next_stride >= iv_type->_hi || // overflow
+            iv_type->_hi + next_stride <  iv_type->_lo) {
           return false;  // over-unrolling
         }
       }
@@ -511,24 +529,33 @@
   // Key test to unroll CaffeineMark's Logic test
   int xors_in_loop = 0;
   // Also count ModL, DivL and MulL which expand mightly
-  for( uint k = 0; k < _body.size(); k++ ) {
-    switch( _body.at(k)->Opcode() ) {
-    case Op_XorI: xors_in_loop++; break; // CaffeineMark's Logic test
-    case Op_ModL: body_size += 30; break;
-    case Op_DivL: body_size += 30; break;
-    case Op_MulL: body_size += 10; break;
-    }
+  for (uint k = 0; k < _body.size(); k++) {
+    Node* n = _body.at(k);
+    switch (n->Opcode()) {
+      case Op_XorI: xors_in_loop++; break; // CaffeineMark's Logic test
+      case Op_ModL: body_size += 30; break;
+      case Op_DivL: body_size += 30; break;
+      case Op_MulL: body_size += 10; break;
+      case Op_StrComp:
+      case Op_StrEquals:
+      case Op_StrIndexOf:
+      case Op_AryEq: {
+        // Do not unroll a loop with String intrinsics code.
+        // String intrinsics are large and have loops.
+        return false;
+      }
+    } // switch
   }
 
   // Check for being too big
-  if( body_size > (uint)LoopUnrollLimit ) {
-    if( xors_in_loop >= 4 && body_size < (uint)LoopUnrollLimit*4) return true;
+  if (body_size > (uint)LoopUnrollLimit) {
+    if (xors_in_loop >= 4 && body_size < (uint)LoopUnrollLimit*4) return true;
     // Normal case: loop too big
     return false;
   }
 
   // Check for stride being a small enough constant
-  if( abs(cl->stride_con()) > (1<<3) ) return false;
+  if (abs(cl->stride_con()) > (1<<3)) return false;
 
   // Unroll once!  (Each trip will soon do double iterations)
   return true;

--- a/hotspot/src/share/vm/opto/memnode.cpp	Wed Mar 30 07:47:19 2011 -0700
+++ b/hotspot/src/share/vm/opto/memnode.cpp	Wed Mar 30 12:08:49 2011 -0700
@@ -2617,54 +2617,24 @@
 }
 
 //=============================================================================
-// Do we match on this edge? No memory edges
-uint StrCompNode::match_edge(uint idx) const {
-  return idx == 2 || idx == 3; // StrComp (Binary str1 cnt1) (Binary str2 cnt2)
-}
-
-//------------------------------Ideal------------------------------------------
-// Return a node which is more "ideal" than the current node.  Strip out
-// control copies
-Node *StrCompNode::Ideal(PhaseGVN *phase, bool can_reshape){
-  return remove_dead_region(phase, can_reshape) ? this : NULL;
-}
-
-//=============================================================================
-// Do we match on this edge? No memory edges
-uint StrEqualsNode::match_edge(uint idx) const {
-  return idx == 2 || idx == 3; // StrEquals (Binary str1 str2) cnt
+// Do not match memory edge.
+uint StrIntrinsicNode::match_edge(uint idx) const {
+  return idx == 2 || idx == 3;
 }
 
 //------------------------------Ideal------------------------------------------
 // Return a node which is more "ideal" than the current node.  Strip out
 // control copies
-Node *StrEqualsNode::Ideal(PhaseGVN *phase, bool can_reshape){
-  return remove_dead_region(phase, can_reshape) ? this : NULL;
-}
-
-//=============================================================================
-// Do we match on this edge? No memory edges
-uint StrIndexOfNode::match_edge(uint idx) const {
-  return idx == 2 || idx == 3; // StrIndexOf (Binary str1 cnt1) (Binary str2 cnt2)
-}
-
-//------------------------------Ideal------------------------------------------
-// Return a node which is more "ideal" than the current node.  Strip out
-// control copies
-Node *StrIndexOfNode::Ideal(PhaseGVN *phase, bool can_reshape){
-  return remove_dead_region(phase, can_reshape) ? this : NULL;
-}
-
-//=============================================================================
-// Do we match on this edge? No memory edges
-uint AryEqNode::match_edge(uint idx) const {
-  return idx == 2 || idx == 3; // StrEquals ary1 ary2
-}
-//------------------------------Ideal------------------------------------------
-// Return a node which is more "ideal" than the current node.  Strip out
-// control copies
-Node *AryEqNode::Ideal(PhaseGVN *phase, bool can_reshape){
-  return remove_dead_region(phase, can_reshape) ? this : NULL;
+Node *StrIntrinsicNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+  if (remove_dead_region(phase, can_reshape)) return this;
+
+  Node* mem = phase->transform(in(MemNode::Memory));
+  // If transformed to a MergeMem, get the desired slice
+  uint alias_idx = phase->C->get_alias_index(adr_type());
+  mem = mem->is_MergeMem() ? mem->as_MergeMem()->memory_at(alias_idx) : mem;
+  if (mem != in(MemNode::Memory))
+    set_req(MemNode::Memory, mem);
+  return NULL;
 }
 
 //=============================================================================

--- a/hotspot/src/share/vm/opto/memnode.hpp	Wed Mar 30 07:47:19 2011 -0700
+++ b/hotspot/src/share/vm/opto/memnode.hpp	Wed Mar 30 12:08:49 2011 -0700
@@ -776,67 +776,69 @@
   static bool step_through(Node** np, uint instance_id, PhaseTransform* phase);
 };
 
-//------------------------------StrComp-------------------------------------
-class StrCompNode: public Node {
+//------------------------------StrIntrinsic-------------------------------
+// Base class for Ideal nodes used in String instrinsic code.
+class StrIntrinsicNode: public Node {
 public:
-  StrCompNode(Node* control, Node* char_array_mem,
-              Node* s1, Node* c1,
-              Node* s2, Node* c2): Node(control, char_array_mem,
-                                        s1, c1,
-                                        s2, c2) {};
-  virtual int Opcode() const;
+  StrIntrinsicNode(Node* control, Node* char_array_mem,
+                   Node* s1, Node* c1, Node* s2, Node* c2):
+    Node(control, char_array_mem, s1, c1, s2, c2) {
+  }
+
+  StrIntrinsicNode(Node* control, Node* char_array_mem,
+                   Node* s1, Node* s2, Node* c):
+    Node(control, char_array_mem, s1, s2, c) {
+  }
+
+  StrIntrinsicNode(Node* control, Node* char_array_mem,
+                   Node* s1, Node* s2):
+    Node(control, char_array_mem, s1, s2) {
+  }
+
   virtual bool depends_only_on_test() const { return false; }
-  virtual const Type* bottom_type() const { return TypeInt::INT; }
   virtual const TypePtr* adr_type() const { return TypeAryPtr::CHARS; }
   virtual uint match_edge(uint idx) const;
   virtual uint ideal_reg() const { return Op_RegI; }
   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 };
 
+//------------------------------StrComp-------------------------------------
+class StrCompNode: public StrIntrinsicNode {
+public:
+  StrCompNode(Node* control, Node* char_array_mem,
+              Node* s1, Node* c1, Node* s2, Node* c2):
+    StrIntrinsicNode(control, char_array_mem, s1, c1, s2, c2) {};
+  virtual int Opcode() const;
+  virtual const Type* bottom_type() const { return TypeInt::INT; }
+};
+
 //------------------------------StrEquals-------------------------------------
-class StrEqualsNode: public Node {
+class StrEqualsNode: public StrIntrinsicNode {
 public:
   StrEqualsNode(Node* control, Node* char_array_mem,
-                Node* s1, Node* s2, Node* c): Node(control, char_array_mem,
-                                                   s1, s2, c) {};
+                Node* s1, Node* s2, Node* c):
+    StrIntrinsicNode(control, char_array_mem, s1, s2, c) {};
   virtual int Opcode() const;
-  virtual bool depends_only_on_test() const { return false; }
   virtual const Type* bottom_type() const { return TypeInt::BOOL; }
-  virtual const TypePtr* adr_type() const { return TypeAryPtr::CHARS; }
-  virtual uint match_edge(uint idx) const;
-  virtual uint ideal_reg() const { return Op_RegI; }
-  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 };
 
 //------------------------------StrIndexOf-------------------------------------
-class StrIndexOfNode: public Node {
+class StrIndexOfNode: public StrIntrinsicNode {
 public:
   StrIndexOfNode(Node* control, Node* char_array_mem,
-                 Node* s1, Node* c1,
-                 Node* s2, Node* c2): Node(control, char_array_mem,
-                                           s1, c1,
-                                           s2, c2) {};
+              Node* s1, Node* c1, Node* s2, Node* c2):
+    StrIntrinsicNode(control, char_array_mem, s1, c1, s2, c2) {};
   virtual int Opcode() const;
-  virtual bool depends_only_on_test() const { return false; }
   virtual const Type* bottom_type() const { return TypeInt::INT; }
-  virtual const TypePtr* adr_type() const { return TypeAryPtr::CHARS; }
-  virtual uint match_edge(uint idx) const;
-  virtual uint ideal_reg() const { return Op_RegI; }
-  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 };
 
 //------------------------------AryEq---------------------------------------
-class AryEqNode: public Node {
+class AryEqNode: public StrIntrinsicNode {
 public:
-  AryEqNode(Node* control, Node* char_array_mem,
-            Node* s1, Node* s2): Node(control, char_array_mem, s1, s2) {};
+  AryEqNode(Node* control, Node* char_array_mem, Node* s1, Node* s2):
+    StrIntrinsicNode(control, char_array_mem, s1, s2) {};
   virtual int Opcode() const;
-  virtual bool depends_only_on_test() const { return false; }
   virtual const Type* bottom_type() const { return TypeInt::BOOL; }
-  virtual const TypePtr* adr_type() const { return TypeAryPtr::CHARS; }
-  virtual uint match_edge(uint idx) const;
-  virtual uint ideal_reg() const { return Op_RegI; }
-  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 };
 
 //------------------------------MemBar-----------------------------------------

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/compiler/7029152/Test.java	Wed Mar 30 12:08:49 2011 -0700
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2011, 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 7029152
+ * @summary Ideal nodes for String intrinsics miss memory edge optimization
+ *
+ * @run main/othervm -Xbatch Test
+ */
+
+public class Test {
+
+  static final String str = "11111xx11111xx1x";
+  static int idx = 0;
+
+  static int IndexOfTest(String str) {
+    return str.indexOf("11111xx1x");
+  }
+
+  public static void main(String args[]) {
+    final int ITERS=2000000;
+
+    for (int i=0; i<ITERS; i++) {
+      idx = IndexOfTest(str);
+    }
+    System.out.println("IndexOf = " + idx);
+  }
+}