Add float to int builtin

compiler/NubLang/Generation/QBE/QBEGenerator.cs

@@ -645,7 +645,8 @@ public class QBEGenerator
             StructFuncCallNode expr => EmitStructFuncCall(expr),
             StructInitializerNode expr => EmitStructInitializer(expr),
             UnaryExpressionNode expr => EmitUnaryExpression(expr),
-            SizeCompilerMacroNode expr => $"{SizeOf(expr.TargetType)}",
+            SizeBuiltinNode expr => $"{SizeOf(expr.TargetType)}",
+            FloatToIntBuiltinNode expr => EmitFloatToIntBuiltin(expr),
             _ => throw new ArgumentOutOfRangeException(nameof(rValue))
         };
     }
@@ -1106,6 +1107,31 @@ public class QBEGenerator
         return result;
     }
 
+    private string EmitFloatToIntBuiltin(FloatToIntBuiltinNode floatToInt)
+    {
+        var value = EmitExpression(floatToInt.Value);
+
+        var method = floatToInt.TargetType.Signed switch
+        {
+            true => floatToInt.ValueType.Width switch
+            {
+                32 => "stosi",
+                64 => "dtosi",
+                _ => throw new ArgumentOutOfRangeException()
+            },
+            false => floatToInt.ValueType.Width switch
+            {
+                32 => "stoui",
+                64 => "dtoui",
+                _ => throw new ArgumentOutOfRangeException()
+            }
+        };
+
+        var result = TmpName();
+        _writer.Indented($"{result} {QBEAssign(floatToInt.TargetType)} {method} {value}");
+        return result;
+    }
+
     private string EmitFuncCall(FuncCallNode funcCall)
     {
         var funcPointer = EmitExpression(funcCall.Expression);