diff --git a/tools/qfcc/include/function.h b/tools/qfcc/include/function.h
index 83b455555..15f32ddc3 100644
--- a/tools/qfcc/include/function.h
+++ b/tools/qfcc/include/function.h
@@ -41,7 +41,8 @@
 
 #include "def.h"
 
-#define MAX_DEF_SIZE ((int)PR_SIZEOF(lvec4))
+// The maximum size of a temp def, return value, or parameter value
+#define MAX_DEF_SIZE 32
 
 /** Represent an overloading of a function.
 
@@ -152,6 +153,7 @@ param_t *check_params (param_t *params);
 
 enum storage_class_e;
 struct defspace_s;
+int value_too_large (struct type_s *val_type) __attribute__((const));
 void make_function (struct symbol_s *sym, const char *nice_name,
 					struct defspace_s *space, enum storage_class_e storage);
 struct symbol_s *function_symbol (struct symbol_s *sym,
diff --git a/tools/qfcc/source/expr.c b/tools/qfcc/source/expr.c
index 65eeb2468..746a94f03 100644
--- a/tools/qfcc/source/expr.c
+++ b/tools/qfcc/source/expr.c
@@ -2197,12 +2197,14 @@ build_function_call (expr_t *fexpr, const type_t *ftype, expr_t *params)
 			return e;
 		}
 
-		if (!type_size (t))
+		if (!type_size (t)) {
 			err = error (e, "type of formal parameter %d is incomplete",
 						 i + 1);
-		if (type_size (t) > type_size (&type_param))
+		}
+		if (value_too_large (t)) {
 			err = error (e, "formal parameter %d is too large to be passed by"
 						 " value", i + 1);
+		}
 		if (i < param_count) {
 			if (e->type == ex_nil)
 				convert_nil (e, t = ftype->t.func.param_types[i]);
diff --git a/tools/qfcc/source/function.c b/tools/qfcc/source/function.c
index e9371ea81..d8642d588 100644
--- a/tools/qfcc/source/function.c
+++ b/tools/qfcc/source/function.c
@@ -459,6 +459,18 @@ find_function (expr_t *fexpr, expr_t *params)
 	return fexpr;
 }
 
+int
+value_too_large (type_t *val_type)
+{
+	if ((options.code.progsversion < PROG_VERSION
+		 && type_size (val_type) > type_size (&type_param))
+		|| (options.code.progsversion == PROG_VERSION
+			&& type_size (val_type) > MAX_DEF_SIZE)) {
+		return 1;
+	}
+	return 0;
+}
+
 static void
 check_function (symbol_t *fsym)
 {
@@ -470,7 +482,7 @@ check_function (symbol_t *fsym)
 		error (0, "return type is an incomplete type");
 		fsym->type->t.func.type = &type_void;//FIXME better type?
 	}
-	if (type_size (fsym->type->t.func.type) > type_size (&type_param)) {
+	if (value_too_large (fsym->type->t.func.type)) {
 		error (0, "return value too large to be passed by value (%d)",
 			   type_size (&type_param));
 		fsym->type->t.func.type = &type_void;//FIXME better type?
@@ -480,12 +492,14 @@ check_function (symbol_t *fsym)
 			continue;					// ellipsis marker
 		if (!p->type)
 			continue;					// non-param selector
-		if (!type_size (p->type))
+		if (!type_size (p->type)) {
 			error (0, "parameter %d (‘%s’) has incomplete type",
 				   i + 1, p->name);
-		if (type_size (p->type) > type_size (&type_param))
+		}
+		if (value_too_large (p->type)) {
 			error (0, "param %d (‘%s’) is too large to be passed by value",
 				   i + 1, p->name);
+		}
 	}
 }