From 4f8e4838e890519b68681e502145ca9170a1adc8 Mon Sep 17 00:00:00 2001
From: Karol Stasiak <karol.m.stasiak@gmail.com>
Date: Sat, 15 Dec 2018 00:01:12 +0100
Subject: [PATCH] 6502: Fix comparison optimization

---
 .../mos/opt/ReverseFlowAnalyzerPerOpcode.scala    | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/main/scala/millfork/assembly/mos/opt/ReverseFlowAnalyzerPerOpcode.scala b/src/main/scala/millfork/assembly/mos/opt/ReverseFlowAnalyzerPerOpcode.scala
index f5b5c8a8..7e997a2d 100644
--- a/src/main/scala/millfork/assembly/mos/opt/ReverseFlowAnalyzerPerOpcode.scala
+++ b/src/main/scala/millfork/assembly/mos/opt/ReverseFlowAnalyzerPerOpcode.scala
@@ -114,27 +114,34 @@ object ReverseFlowAnalyzerPerOpcode {
     CMP -> (currentImportance => {
       val ignoreOutput = allCompareOutputsAreUnimportant(currentImportance)
       currentImportance.copy(
-        a = if (ignoreOutput) Unimportant else Important,
+        a = if (ignoreOutput) currentImportance.a else Important,
         n = Unimportant, z = Unimportant, c = Unimportant,
         m = Important)
     }),
     DCP -> (currentImportance => {
       val ignoreOutput = allCompareOutputsAreUnimportant(currentImportance)
       currentImportance.copy(
-        a = if (ignoreOutput) Unimportant else Important,
+        a = if (ignoreOutput) currentImportance.a else Important,
         n = Unimportant, z = Unimportant, c = Unimportant)
     }),
     CPX -> (currentImportance => {
       val ignoreOutput = allCompareOutputsAreUnimportant(currentImportance)
       currentImportance.copy(
-        x = if (ignoreOutput) Unimportant else Important,
+        x = if (ignoreOutput) currentImportance.x else Important,
         n = Unimportant, z = Unimportant, c = Unimportant,
         w = Important)
     }),
     CPY -> (currentImportance => {
       val ignoreOutput = allCompareOutputsAreUnimportant(currentImportance)
       currentImportance.copy(
-        y = if (ignoreOutput) Unimportant else Important,
+        y = if (ignoreOutput) currentImportance.y else Important,
+        n = Unimportant, z = Unimportant, c = Unimportant,
+        w = Important)
+    }),
+    CPZ -> (currentImportance => {
+      val ignoreOutput = allCompareOutputsAreUnimportant(currentImportance)
+      currentImportance.copy(
+        iz = if (ignoreOutput) currentImportance.iz else Important,
         n = Unimportant, z = Unimportant, c = Unimportant,
         w = Important)
     }),