From: Clifford Wolf <clifford@clifford.at>
Date: Thu, 14 Mar 2019 16:51:21 +0000 (+0100)
Subject: Improve handling of "full_case" attributes
X-Git-Tag: yosys-0.9~242^2
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=17caaa3fa898e39d1dbcfd8b92750a9d713a24af;p=yosys.git

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 d7da6fb40..b3a2a84be 100644
--- 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;