Commit 128814f9bf

@@ -4926,6 +4926,9 @@ fn airAggregateInit(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
                 const result = try func.allocStack(result_ty);
                 const elem_ty = result_ty.childType();
                 const elem_size = @intCast(u32, elem_ty.abiSize(func.target));
+                const sentinel = if (result_ty.sentinel()) |sent| blk: {
+                    break :blk try func.lowerConstant(sent, elem_ty);
+                } else null;
 
                 // When the element type is by reference, we must copy the entire
                 // value. It is therefore safer to move the offset pointer and store
@@ -4938,10 +4941,13 @@ fn airAggregateInit(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
                         const elem_val = try func.resolveInst(elem);
                         try func.store(offset, elem_val, elem_ty, 0);
 
-                        if (elem_index < elements.len - 1) {
+                        if (elem_index < elements.len - 1 and sentinel == null) {
                             _ = try func.buildPointerOffset(offset, elem_size, .modify);
                         }
                     }
+                    if (sentinel) |sent| {
+                        try func.store(offset, sent, elem_ty, 0);
+                    }
                 } else {
                     var offset: u32 = 0;
                     for (elements) |elem| {
@@ -4949,6 +4955,9 @@ fn airAggregateInit(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
                         try func.store(result, elem_val, elem_ty, offset);
                         offset += elem_size;
                     }
+                    if (sentinel) |sent| {
+                        try func.store(result, sent, elem_ty, offset);
+                    }
                 }
                 break :result_value result;
             },