From 0694a187d76e900b20030d027ceff4ccf2cd4618 Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Mon, 12 Dec 2022 20:37:57 +0100
Subject: [PATCH] unsigned>0 now optimized into unsigned!=0

---
 .../src/prog8/optimizer/ExpressionSimplifier.kt  | 16 ++++++++++++----
 docs/source/todo.rst                             |  1 +
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/codeOptimizers/src/prog8/optimizer/ExpressionSimplifier.kt b/codeOptimizers/src/prog8/optimizer/ExpressionSimplifier.kt
index 9234081fb..86b9d0b24 100644
--- a/codeOptimizers/src/prog8/optimizer/ExpressionSimplifier.kt
+++ b/codeOptimizers/src/prog8/optimizer/ExpressionSimplifier.kt
@@ -193,11 +193,15 @@ class ExpressionSimplifier(private val program: Program,
             return listOf(IAstModification.ReplaceNode(expr.right, NumericLiteral.optimalInteger(0, expr.right.position), expr))
         }
 
-        if(expr.operator == ">=" && rightVal?.number == 0.0) {
-            if (leftDt == DataType.UBYTE || leftDt == DataType.UWORD) {
+        if (leftDt == DataType.UBYTE || leftDt == DataType.UWORD) {
+            if(expr.operator == ">=" && rightVal?.number == 0.0) {
                 // unsigned >= 0 --> true
                 return listOf(IAstModification.ReplaceNode(expr, NumericLiteral.fromBoolean(true, expr.position), parent))
             }
+            else if(expr.operator == ">" && rightVal?.number == 0.0) {
+                // unsigned > 0 --> unsigned != 0
+                return listOf(IAstModification.SetExpression({expr.operator="!="}, expr, parent))
+            }
         }
 
         if(leftDt!=DataType.FLOAT && expr.operator == "<" && rightVal?.number == 1.0) {
@@ -206,11 +210,15 @@ class ExpressionSimplifier(private val program: Program,
             return listOf(IAstModification.ReplaceNode(expr.right, NumericLiteral.optimalInteger(0, expr.right.position), expr))
         }
 
-        if(expr.operator == "<" && rightVal?.number == 0.0) {
-            if (leftDt == DataType.UBYTE || leftDt == DataType.UWORD) {
+        if (leftDt == DataType.UBYTE || leftDt == DataType.UWORD) {
+            if(expr.operator == "<" && rightVal?.number == 0.0) {
                 // unsigned < 0 --> false
                 return listOf(IAstModification.ReplaceNode(expr, NumericLiteral.fromBoolean(false, expr.position), parent))
             }
+            else if(expr.operator == "<=" && rightVal?.number == 0.0) {
+                // unsigned <= 0 --> unsigned==0
+                return listOf(IAstModification.SetExpression({expr.operator="=="}, expr, parent))
+            }
         }
 
         // boolvar & 1  --> boolvar
diff --git a/docs/source/todo.rst b/docs/source/todo.rst
index 0d0fdfe4f..fd843c093 100644
--- a/docs/source/todo.rst
+++ b/docs/source/todo.rst
@@ -3,6 +3,7 @@ TODO
 
 For next release
 ^^^^^^^^^^^^^^^^
+- "until not bytearray[index]" creates some pretty silly assembly code. what about while? if?
 - regression test the various projects before release
 
 ...