store-store opt checks offset

2 files changed, 15 insertions, 0 deletions

diff --git a/chapter15/src/main/java/com/seaofnodes/simple/node/StoreNode.java b/chapter15/src/main/java/com/seaofnodes/simple/node/StoreNode.java
index a27aee2b..6bdbbc61 100644
--- a/chapter15/src/main/java/com/seaofnodes/simple/node/StoreNode.java
+++ b/chapter15/src/main/java/com/seaofnodes/simple/node/StoreNode.java
@@ -53,6 +53,7 @@ public class StoreNode extends MemOpNode {
         // required init-store being stomped by a first user store.
         if( mem() instanceof StoreNode st &&
             ptr()==st.ptr() &&  // Must check same object
+            off()==st.off() &&  // And same offset
             ptr()._type instanceof TypeMemPtr && // No bother if weird dead pointers
             // Must have exactly one use of "this" or you get weird
             // non-serializable memory effects in the worse case.
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter15Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter15Test.java
index f08abed0..6ba6eed4 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter15Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter15Test.java
@@ -47,6 +47,20 @@ return is[1];
     }
 
     @Test
+    public void testBasic3() {
+        Parser parser = new Parser(
+"""
+int[] a = new int[2];
+a[0] = 1;
+a[1] = 2;
+return a[0];
+""");
+        StopNode stop = parser.parse(false).iterate(true);
+        assertEquals("return .[];", stop.toString());
+        assertEquals(1L, Evaluator.evaluate(stop,  0));
+    }
+
+    @Test
     public void testRollingSum() {
         Parser parser = new Parser(
 """