Improve handling of "full_case" attributes

Signed-off-by: Clifford Wolf <clifford@clifford.at>

diff --git a/frontends/ast/genrtlil.cc b/frontends/ast/genrtlil.cc
index d7da6fb406246aaf948a26d877fc7e22bb6eeafd..b3a2a84be51e99e6e45c7b05cdcb7b7620b4bde8 100644 (file)
--- a/frontends/ast/genrtlil.cc
+++ b/frontends/ast/genrtlil.cc
@@ -525,7 +525,16 @@ struct AST_INTERNAL::ProcessGenerator
                                }
 
                                if (last_generated_case != NULL && ast->get_bool_attribute("\\full_case") && default_case == NULL) {
+                       #if 0
+                                       // this is a valid transformation, but as optimization it is premature.
+                                       // better: add a default case that assigns 'x' to everything, and let later
+                                       // optimizations take care of the rest
                                        last_generated_case->compare.clear();
+                       #else
+                                       default_case = new RTLIL::CaseRule;
+                                       addChunkActions(default_case->actions, this_case_eq_ltemp, SigSpec(State::Sx, GetSize(this_case_eq_rvalue)));
+                                       sw->cases.push_back(default_case);
+                       #endif
                                } else {
                                        if (default_case == NULL) {
                                                default_case = new RTLIL::CaseRule;