From: Clifford Wolf <clifford@clifford.at>
Date: Fri, 8 Nov 2013 03:44:09 +0000 (+0100)
Subject: Implemented const folding of ternary op with undef select
X-Git-Tag: yosys-0.2.0~381
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=4abc8e695ad0b3b11ae687d776856dd98b56101d;p=yosys.git

Implemented const folding of ternary op with undef select
---

diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index 5c0130d42..9fa7f558b 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -1074,6 +1074,14 @@ skip_dynamic_range_lvalue_expansion:;
 				if (choice != NULL && choice->type == AST_CONSTANT) {
 					RTLIL::Const y = choice->bitsAsConst(width_hint, sign_hint);
 					newNode = mkconst_bits(y.bits, sign_hint);
+				} else if (children[1]->type == AST_CONSTANT && children[2]->type == AST_CONSTANT) {
+					RTLIL::Const a = children[1]->bitsAsConst(width_hint, sign_hint);
+					RTLIL::Const b = children[2]->bitsAsConst(width_hint, sign_hint);
+					assert(a.bits.size() == b.bits.size());
+					for (size_t i = 0; i < a.bits.size(); i++)
+						if (a.bits[i] != b.bits[i])
+							a.bits[i] = RTLIL::State::Sx;
+					newNode = mkconst_bits(a.bits, sign_hint);
 				}
 			}
 			break;