Clarify address target optimization test

Author: bertysentry

src/main/java/io/jawk/intermediate/AwkTuples.java

@@ -1882,7 +1882,7 @@ private boolean peepholeOptimizePass() {
 		int[] indexMapping = new int[originalSize];
 		Arrays.fill(indexMapping, -1);
 		java.util.List<Tuple> optimizedQueue = new ArrayList<Tuple>(originalSize);
-		boolean[] addressTargets = addressTargets(original, originalSize);
+		boolean[] isAddressTarget = addressTargets(original, originalSize);
 
 		boolean modified = false;
 		int oldIndex = 0;
@@ -1898,7 +1898,7 @@ private boolean peepholeOptimizePass() {
 				// unless the POP itself is a branch target. Branches that land on
 				// the POP must continue to skip the assignment and only discard the
 				// already-computed expression result.
-				if (nextTuple.getOpcode() == Opcode.POP && !addressTargets[oldIndex + 1]) {
+				if (nextTuple.getOpcode() == Opcode.POP && !isAddressTarget[oldIndex + 1]) {
 					Tuple replacement = createAssignNoPush(tuple);
 					optimizedQueue.add(replacement);
 					mapFoldedRange(indexMapping, oldIndex, 2, newIndex);

src/test/java/io/jawk/AwkTupleOptimizationTest.java

@@ -181,7 +181,7 @@ public void keepsAssignmentPopWhenPopIsBranchTarget() throws Exception {
 		AwkProgram tuples = new Awk().compile(script);
 		assertTrue(
 				"ASSIGN followed by targeted POP should not be folded",
-				hasAdjacentOpcodes(tuples, Opcode.ASSIGN, Opcode.POP));
+				hasAddressTargetWithPredecessor(tuples, Opcode.ASSIGN, Opcode.POP));
 	}
 
 	@Test
@@ -533,6 +533,31 @@ private static boolean hasAdjacentOpcodes(AwkProgram tuples, Opcode first, Opcod
 		return false;
 	}
 
+	private static boolean hasAddressTargetWithPredecessor(AwkProgram tuples, Opcode predecessor, Opcode target) {
+		Set<Integer> targetIndexes = new HashSet<>();
+		PositionTracker tracker = rawTuples(tuples).top();
+		while (!tracker.isEOF()) {
+			Address address = tracker.current().getAddress();
+			if (address != null) {
+				targetIndexes.add(Integer.valueOf(address.index()));
+			}
+			tracker.next();
+		}
+
+		tracker = rawTuples(tuples).top();
+		Opcode previous = null;
+		while (!tracker.isEOF()) {
+			if (targetIndexes.contains(Integer.valueOf(tracker.currentIndex()))
+					&& previous == predecessor
+					&& tracker.opcode() == target) {
+				return true;
+			}
+			previous = tracker.opcode();
+			tracker.next();
+		}
+		return false;
+	}
+
 	private static int countOpcode(AwkProgram tuples, Opcode opcode) {
 		int count = 0;
 		PositionTracker tracker = rawTuples(tuples).top();