From 7d180069e398734fac04c385f4732668eeee4b75 Mon Sep 17 00:00:00 2001
From: Chronos Ouroboros <doom2.fan@gmail.com>
Date: Mon, 17 Feb 2025 06:53:26 -0300
Subject: [PATCH] Fix FxExpression::EmitCompare not properly handling constant
 registers.

---
 src/common/scripting/backend/codegen.cpp | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/src/common/scripting/backend/codegen.cpp b/src/common/scripting/backend/codegen.cpp
index 10dc29576..92b68d703 100644
--- a/src/common/scripting/backend/codegen.cpp
+++ b/src/common/scripting/backend/codegen.cpp
@@ -387,6 +387,30 @@ void FxExpression::EmitCompare(VMFunctionBuilder *build, bool invert, TArray<siz
 	if (op.Konst)
 	{
 		ScriptPosition.Message(MSG_WARNING, "Conditional expression is constant");
+		ExpEmit temp(build, op.RegType);
+		switch (op.RegType)
+		{
+		case REGT_INT:
+			build->Emit(OP_LK, temp.RegNum, op.RegNum);
+			break;
+
+		case REGT_FLOAT:
+			build->Emit(OP_LKF, temp.RegNum, op.RegNum);
+			break;
+
+		case REGT_POINTER:
+			build->Emit(OP_LKP, temp.RegNum, op.RegNum);
+			break;
+
+		case REGT_STRING:
+			build->Emit(OP_LKS, temp.RegNum, op.RegNum);
+			break;
+
+		default:
+			break;
+		}
+		op.Free(build);
+		op = temp;
 	}
 	switch (op.RegType)
 	{