From 48b00dcceab8bb046258cd6f0912636a6e5b232c Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Mon, 8 Sep 2014 12:25:23 +0200
Subject: [PATCH] Another $clog2 bugfix

---
 frontends/ast/simplify.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index 9e797573c..969cc2302 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -1365,6 +1365,8 @@ skip_dynamic_range_lvalue_expansion:;
 					log_error("Failed to evaluate system function `%s' with non-constant value at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
 
 				RTLIL::Const arg_value = buf->bitsAsConst();
+				if (arg_value.as_bool())
+					arg_value = const_sub(arg_value, 1, false, false, SIZE(arg_value));
 				delete buf;
 
 				uint32_t result = 0;