Fix memory on Load splitting up

2 files changed, 4 insertions, 1 deletions

diff --git a/chapter16/src/main/java/com/seaofnodes/simple/Parser.java b/chapter16/src/main/java/com/seaofnodes/simple/Parser.java
index 41a3fcaa..b4cfaaf3 100644
--- a/chapter16/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter16/src/main/java/com/seaofnodes/simple/Parser.java
@@ -910,7 +910,7 @@ public class Parser {
         // Arrays include control, as a proxy for a safety range check
         // Structs don't need this; they only need a NPE check which is
         // done via the type system.
-        //if( base.isAry() ) load.setDef(0,ctrl());
+        if( base.isAry() ) load.setDef(0,ctrl());
         return parsePostfix(load.peephole());
     }
 
diff --git a/chapter16/src/main/java/com/seaofnodes/simple/node/LoadNode.java b/chapter16/src/main/java/com/seaofnodes/simple/node/LoadNode.java
index 8d604b28..ab53aa6a 100644
--- a/chapter16/src/main/java/com/seaofnodes/simple/node/LoadNode.java
+++ b/chapter16/src/main/java/com/seaofnodes/simple/node/LoadNode.java
@@ -122,6 +122,9 @@ public class LoadNode extends MemOpNode {
         //   else       ptr.x = e1;                    : e1;
         //   val = ptr.x;                   ptr.x = val;
         if( mem() instanceof MemPhiNode memphi && memphi.region()._type == Type.CONTROL && memphi.nIns()== 3 &&
+            // Retain control on both copies only if it dominates both paths.
+            // The Region itself, or a later range check, cannot move to its inputs.
+            (in(0)==null || cfg0().domLCA(memphi.region().idom(this),this)==cfg0()) &&
             off() instanceof ConstantNode ) {
             // Profit on RHS/Loop backedge
             if( profit(memphi,2) ||