ast_function: Set constant_value on return value temporaries in 1.20+.
diff --git a/src/glsl/ast_function.cpp b/src/glsl/ast_function.cpp
index 855f27f..bb45e25 100644
--- a/src/glsl/ast_function.cpp
+++ b/src/glsl/ast_function.cpp
@@ -122,6 +122,8 @@
deref = new(ctx) ir_dereference_variable(var);
ir_assignment *assign = new(ctx) ir_assignment(deref, call, NULL);
instructions->push_tail(assign);
+ if (state->language_version >= 120)
+ var->constant_value = call->constant_expression_value();
deref = new(ctx) ir_dereference_variable(var);
return deref;