...

example/src/main.nub

@@ -1,29 +1,31 @@
 namespace main
 
-struct Name {
-    first: cstring
-    last: cstring
-}
+// struct Name {
+//     first: cstring
+//     last: cstring
+// }
 
-struct Human
-{
-    name: Name
-    age: i64
-}
+// struct Human
+// {
+//     name: Name
+//     age: i64
+// }
 
 export func main(args: []cstring): i64
 {
-    let x: Human
+    // let x: Human
 
-    x = alloc Human {
-        name = alloc Name {
-            first = "john"
-            last = "doe"
-        }
-        age = 23
-    }
+    // x = alloc Human {
+    //     name = alloc Name {
+    //         first = "john"
+    //         last = "doe"
+    //     }
+    //     age = 23
+    // }
 
-    c::puts(x.name.last)
+    // c::puts(x.name.last)
+
+    c::puts("test")
 
     return 0
 }

src/compiler/Generation/QBE/QBEGenerator.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Text;
 using Syntax;
@@ -219,8 +220,9 @@ public static class QBEGenerator
         return false;
     }
 
-    private static void EmitCopyOrMoveInto(BoundExpressionNode source, string destinationPointer)
+    private static void EmitCopyIntoOrInitialize(BoundExpressionNode source, string destinationPointer)
     {
+        // If the source is a value which is not used yet such as an array/struct initializer or literal, we can skip copying
         if (EmitTryMoveInto(source, destinationPointer))
         {
             return;
@@ -276,8 +278,33 @@ public static class QBEGenerator
         }
     }
 
-    private static string EmitCopy(NubType type, string source)
+    private static bool EmitTryCreateWithoutCopy(BoundExpressionNode source, [NotNullWhen(true)] out string? destination)
     {
+        switch (source)
+        {
+            case BoundArrayInitializerNode:
+            case BoundStructInitializerNode:
+            case BoundLiteralNode { Kind: LiteralKind.String }:
+            {
+                destination = EmitUnwrap(EmitExpression(source));
+                return true;
+            }
+        }
+
+        destination = null;
+        return false;
+    }
+
+    private static string EmitCreateCopyOrInitialize(NubType type, BoundExpressionNode source)
+    {
+        // If the source is a value which is not used yet such as an array/struct initializer or literal, we can skip copying
+        if (EmitTryCreateWithoutCopy(source, out var uncopiedValue))
+        {
+            return uncopiedValue;
+        }
+
+        var value = EmitUnwrap(EmitExpression(source));
+
         switch (type)
         {
             case NubComplexType complexType:
@@ -286,20 +313,20 @@ public static class QBEGenerator
 
                 var size = complexType switch
                 {
-                    NubArrayType nubArrayType => EmitArraySizeInBytes(nubArrayType, source),
-                    NubCStringType => EmitCStringSizeInBytes(source),
-                    NubStringType => EmitStringSizeInBytes(source),
+                    NubArrayType nubArrayType => EmitArraySizeInBytes(nubArrayType, value),
+                    NubCStringType => EmitCStringSizeInBytes(value),
+                    NubStringType => EmitStringSizeInBytes(value),
                     NubStructType nubStructType => SizeOf(nubStructType).ToString(),
                     _ => throw new ArgumentOutOfRangeException(nameof(complexType))
                 };
 
                 _builder.AppendLine($"    {destination} =l alloc8 {size}");
-                EmitMemcpy(source, destination, size);
+                EmitMemcpy(value, destination, size);
                 return destination;
             }
             case NubSimpleType:
             {
-                return source;
+                return value;
             }
             default:
             {
@@ -601,7 +628,7 @@ public static class QBEGenerator
     {
         var destination = EmitExpression(assignment.Expression);
         Debug.Assert(destination.Kind == ValKind.Pointer);
-        EmitCopyOrMoveInto(assignment.Value, destination.Name);
+        EmitCopyIntoOrInitialize(assignment.Value, destination.Name);
     }
 
     private static void EmitBlock(BoundBlockNode block, List<Variable>? variables = null)
@@ -1039,7 +1066,7 @@ public static class QBEGenerator
 
             var offset = VarName();
             _builder.AppendLine($"    {offset} =l add {destination}, {OffsetOf(structDefinition, field.Name)}");
-            EmitCopyOrMoveInto(valueExpression, offset);
+            EmitCopyIntoOrInitialize(valueExpression, offset);
         }
 
         return new Val(destination, structInitializer.StructType, ValKind.Direct);
@@ -1169,7 +1196,7 @@ public static class QBEGenerator
                 _ => throw new NotSupportedException($"'{parameter.Type}' type cannot be used in function calls")
             };
 
-            var copy = EmitCopy(parameter.Type, EmitUnwrap(EmitExpression(parameter)));
+            var copy = EmitCreateCopyOrInitialize(parameter.Type, parameter);
             parameterStrings.Add($"{qbeType} {copy}");
         }