diff --git a/src/stage1/codegen.cpp b/src/stage1/codegen.cpp
index fcb3282d06..389ede91b7 100644
--- a/src/stage1/codegen.cpp
+++ b/src/stage1/codegen.cpp
@@ -549,7 +549,7 @@ static LLVMValueRef make_fn_llvm_value(CodeGen *g, ZigFn *fn) {
         } else if (want_first_arg_sret(g, &fn_type->data.fn.fn_type_id)) {
             // Sret pointers must not be address 0
             addLLVMArgAttr(llvm_fn, 0, "nonnull");
-            addLLVMArgAttr(llvm_fn, 0, "sret");
+            ZigLLVMAddSretAttr(llvm_fn, 0, get_llvm_type(g, return_type));
             if (cc_want_sret_attr(cc)) {
                 addLLVMArgAttr(llvm_fn, 0, "noalias");
             }
@@ -1972,7 +1972,7 @@ static bool iter_function_params_c_abi(CodeGen *g, ZigType *fn_type, FnWalk *fn_
             switch (fn_walk->id) {
                 case FnWalkIdAttrs:
                     if (abi_class != X64CABIClass_MEMORY_nobyval) {
-                        ZigLLVMAddByValAttr(llvm_fn, fn_walk->data.attrs.gen_i + 1, get_llvm_type(g, ty));
+                        ZigLLVMAddByValAttr(llvm_fn, fn_walk->data.attrs.gen_i, get_llvm_type(g, ty));
                         addLLVMArgAttrInt(llvm_fn, fn_walk->data.attrs.gen_i, "align", get_abi_alignment(g, ty));
                     } else if (g->zig_target->arch == ZigLLVM_aarch64 ||
                             g->zig_target->arch == ZigLLVM_aarch64_be)
diff --git a/src/zig_llvm.cpp b/src/zig_llvm.cpp
index b4bdf7c033..55e507c6d0 100644
--- a/src/zig_llvm.cpp
+++ b/src/zig_llvm.cpp
@@ -798,7 +798,17 @@ void ZigLLVMAddByValAttr(LLVMValueRef fn_ref, unsigned ArgNo, LLVMTypeRef type_v
     AttrBuilder attr_builder;
     Type *llvm_type = unwrap<Type>(type_val);
     attr_builder.addByValAttr(llvm_type);
-    const AttributeList new_attr_set = attr_set.addAttributes(func->getContext(), ArgNo, attr_builder);
+    const AttributeList new_attr_set = attr_set.addAttributes(func->getContext(), ArgNo + 1, attr_builder);
+    func->setAttributes(new_attr_set);
+}
+
+void ZigLLVMAddSretAttr(LLVMValueRef fn_ref, unsigned ArgNo, LLVMTypeRef type_val) {
+    Function *func = unwrap<Function>(fn_ref);
+    const AttributeList attr_set = func->getAttributes();
+    AttrBuilder attr_builder;
+    Type *llvm_type = unwrap<Type>(type_val);
+    attr_builder.addStructRetAttr(llvm_type);
+    const AttributeList new_attr_set = attr_set.addAttributes(func->getContext(), ArgNo + 1, attr_builder);
     func->setAttributes(new_attr_set);
 }
 
diff --git a/src/zig_llvm.h b/src/zig_llvm.h
index fc9f39d9e9..c8ffa32e81 100644
--- a/src/zig_llvm.h
+++ b/src/zig_llvm.h
@@ -269,6 +269,7 @@ ZIG_EXTERN_C void ZigLLVMFunctionSetCallingConv(LLVMValueRef function, enum ZigL
 
 ZIG_EXTERN_C void ZigLLVMAddFunctionAttr(LLVMValueRef fn, const char *attr_name, const char *attr_value);
 ZIG_EXTERN_C void ZigLLVMAddByValAttr(LLVMValueRef fn_ref, unsigned ArgNo, LLVMTypeRef type_val);
+ZIG_EXTERN_C void ZigLLVMAddSretAttr(LLVMValueRef fn_ref, unsigned ArgNo, LLVMTypeRef type_val);
 ZIG_EXTERN_C void ZigLLVMAddFunctionAttrCold(LLVMValueRef fn);
 
 ZIG_EXTERN_C void ZigLLVMParseCommandLineOptions(size_t argc, const char *const *argv);