fix array out of bounds issue

compiler/src/l3/CPSValueRepresenter.scala

@@ -56,11 +56,7 @@ object CPSValueRepresenter extends (H.Tree => L.Tree) {
     }
   }
 
-  private def rewriteIndex(idx: H.Atom): L.Atom = idx match {
-    case H.AtomN(n) => L.AtomN(n)
-    case H.AtomL(IntLit(i)) => L.AtomL(i.toInt)
-    case _ => throw new Exception(f"Cannot rewrite atom {idx} which is not Name or Int Literal")
-  }
+  
 
   private def getMaskR(numBits: Int): Either[H.Atom, L.Atom] = Right(L.AtomL((1 << numBits) -1))
 
@@ -87,15 +83,6 @@ object CPSValueRepresenter extends (H.Tree => L.Tree) {
     }
 
     prim match {
-      case L3.BlockSet => 
-        val block = rewrite(x)
-        val idx = rewriteIndex(y)
-        val value = rewrite(z)
-        L.LetP(n, CPS.BlockSet, Seq(block, idx, value), apply(body))
-      case L3.BlockGet => 
-        val block = rewrite(x)
-        val idx = rewriteIndex(y)
-        L.LetP(n, CPS.BlockGet, Seq(block, idx), apply(body))
       case L3.IntAdd => 
         tempLetP(CPS.Sub, Seq(Left(x), lAtomOne)) { x1 => 
           L.LetP(n, CPS.Add, Seq(x1, rewrite(y)), apply(body))
@@ -146,21 +133,29 @@ object CPSValueRepresenter extends (H.Tree => L.Tree) {
 
 
       case L3.BlockAlloc(tag) => 
-        tempLetP(CPS.ShiftRight, Seq(Right(rewrite(x)), lAtomOne)) { t1 =>
+        tempLetP(CPS.ShiftRight, Seq(Left(x), lAtomOne)) { t1 =>
           L.LetP(n, CPS.BlockAlloc(tag), Seq(t1), apply(body))
         }
       case L3.BlockTag =>
-        tempLetP(CPS.BlockTag, args map (x => Right(rewrite(x)))) { t1 =>
+        tempLetP(CPS.BlockTag, args map (Left(_))) { t1 =>
           tempLetP(CPS.ShiftLeft, Seq(Right(t1), lAtomOne)) { t2 =>
             L.LetP(n, CPS.Add, Seq(t2, L.AtomL(1)), apply(body))
           }
         }
       case L3.BlockLength => 
-        tempLetP(CPS.BlockLength, args map (x => Left(x))) { t1 =>
+        tempLetP(CPS.BlockLength, args map (Left(_))) { t1 =>
           tempLetP(CPS.ShiftLeft, Seq(Right(t1), Right(L.AtomL(1)))) { t2 =>
             L.LetP(n, CPS.Add, Seq(t2, L.AtomL(1)), apply(body))
           }
         }
+      case L3.BlockSet => 
+        val block = rewrite(x)
+        val value = rewrite(z)
+        rewriteIndex(y) {idx => L.LetP(n, CPS.BlockSet, Seq(block, idx, value), apply(body))}
+      case L3.BlockGet => 
+        val block = rewrite(x)
+        rewriteIndex(y){idx => L.LetP(n, CPS.BlockGet, Seq(block, idx), apply(body))}
+
 
       case L3.ByteRead =>
         tempLetP(CPS.ByteRead, Seq()){ t1 => 
@@ -211,4 +206,11 @@ object CPSValueRepresenter extends (H.Tree => L.Tree) {
         L.AtomL(0x0a) // 01010
     case H.AtomL(UnitLit) => L.AtomL(2)
   }
+
+  private def rewriteIndex(idx: H.Atom)(cont: L.Atom => L.LetP): L.LetP = idx match {
+    case H.AtomN(n) => 
+      tempLetP(CPS.ShiftRight, Seq(Left(idx), Right(L.AtomL(1))))(cont)
+    case H.AtomL(IntLit(i)) => cont(L.AtomL(i.toInt))
+    case _ => throw new Exception(f"Cannot rewrite atom {idx} which is not Name or Int Literal")
+  }
 }