From ea0c634e12cb122113a9b97eb66a0efbda082aa6 Mon Sep 17 00:00:00 2001
From: acqn <acqn163@outlook.com>
Date: Tue, 23 Feb 2021 17:39:02 +0800
Subject: [PATCH] Improved codegen for unsigned char type comparison with
 numeric constants.

---
 src/cc65/expr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cc65/expr.c b/src/cc65/expr.c
index 083d1dc99..66c633d2e 100644
--- a/src/cc65/expr.c
+++ b/src/cc65/expr.c
@@ -2845,7 +2845,7 @@ static void hie_compare (const GenDesc* Ops,    /* List of generators */
             }
 
             /* Determine the type of the operation. */
-            if (IsTypeChar (Expr->Type) && rconst && RightSigned) {
+            if (IsTypeChar (Expr->Type) && rconst && (!LeftSigned || RightSigned)) {
 
                 /* Left side is unsigned char, right side is constant.
                 ** Determine the minimum and maximum values
@@ -2923,7 +2923,7 @@ static void hie_compare (const GenDesc* Ops,    /* List of generators */
                 ** since the right side constant is in a valid range.
                 */
                 flags |= (CF_CHAR | CF_FORCECHAR);
-                if (!LeftSigned) {
+                if (!LeftSigned || !RightSigned) {
                     flags |= CF_UNSIGNED;
                 }