From 7e4585a5e6e2776cce34932d8b8c8a7ed3a5691e Mon Sep 17 00:00:00 2001
From: kvn <unknown>
Date: Thu, 31 Mar 2011 13:22:34 -0700
Subject: [PATCH] 7032696: Fix for 7029152 broke VM Summary:
 StrIntrinsicNode::Ideal() should not optimize memory during Parse.
 Reviewed-by: jrose, never

---
 src/share/vm/opto/loopTransform.cpp |  6 ++++++
 src/share/vm/opto/memnode.cpp       | 16 ++++++++++------
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/share/vm/opto/loopTransform.cpp b/src/share/vm/opto/loopTransform.cpp
index e386dcd59..4c49ee0e6 100644
--- a/src/share/vm/opto/loopTransform.cpp
+++ b/src/share/vm/opto/loopTransform.cpp
@@ -432,6 +432,12 @@ bool IdealLoopTree::policy_maximally_unroll( PhaseIdealLoop *phase ) const {
     return false;
   }
 
+  // Currently we don't have policy to optimize one iteration loops.
+  // Maximally unrolling transformation is used for that:
+  // it is peeled and the original loop become non reachable (dead).
+  if (trip_count == 1)
+    return true;
+
   // Do not unroll a loop with String intrinsics code.
   // String intrinsics are large and have loops.
   for (uint k = 0; k < _body.size(); k++) {
diff --git a/src/share/vm/opto/memnode.cpp b/src/share/vm/opto/memnode.cpp
index 4c6878d3f..d5d53132a 100644
--- a/src/share/vm/opto/memnode.cpp
+++ b/src/share/vm/opto/memnode.cpp
@@ -2628,12 +2628,16 @@ uint StrIntrinsicNode::match_edge(uint idx) const {
 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);
+  if (can_reshape) {
+    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 this;
+    }
+  }
   return NULL;
 }
 
-- 
GitLab