4 files changed, 22 insertions, 0 deletions
diff --git a/frontends/ast/ast.cc b/frontends/ast/ast.cc
index 40f7826f..96608ae3 100644
--- a/frontends/ast/ast.cc
+++ b/frontends/ast/ast.cc
@@ -82,6 +82,7 @@ std::string AST::type2str(AstNodeType type)
 	X(AST_PREFIX)
 	X(AST_ASSERT)
 	X(AST_FCALL)
+	X(AST_TO_BITS)
 	X(AST_TO_SIGNED)
 	X(AST_TO_UNSIGNED)
 	X(AST_CONCAT)
diff --git a/frontends/ast/ast.h b/frontends/ast/ast.h
index caae679a..01702c3c 100644
--- a/frontends/ast/ast.h
+++ b/frontends/ast/ast.h
@@ -61,6 +61,7 @@ namespace AST
 		AST_ASSERT,
 
 		AST_FCALL,
+		AST_TO_BITS,
 		AST_TO_SIGNED,
 		AST_TO_UNSIGNED,
 		AST_CONCAT,
diff --git a/frontends/ast/genrtlil.cc b/frontends/ast/genrtlil.cc
index 6001e278..99d8566d 100644
--- a/frontends/ast/genrtlil.cc
+++ b/frontends/ast/genrtlil.cc
@@ -664,6 +664,14 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint)
 			sign_hint = false;
 		break;
 
+	case AST_TO_BITS:
+		while (children[0]->simplify(true, false, false, 1, -1, false) == true) { }
+		if (children[0]->type != AST_CONSTANT)
+			log_error("Left operand of tobits expression is not constant at %s:%d!\n", filename.c_str(), linenum);
+		children[1]->detectSignWidthWorker(sub_width_hint, sign_hint);
+		width_hint = std::max(width_hint, children[0]->bitsAsConst().as_int());
+		break;
+
 	case AST_TO_SIGNED:
 		children.at(0)->detectSignWidthWorker(width_hint, sub_sign_hint);
 		break;
diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index 5a2d1ae6..f19befe2 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -258,6 +258,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		}
 		break;
 
+	case AST_TO_BITS:
 	case AST_TO_SIGNED:
 	case AST_TO_UNSIGNED:
 	case AST_CONCAT:
@@ -442,6 +443,17 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		goto apply_newNode;
 	}
 
+	// evaluate TO_BITS nodes
+	if (type == AST_TO_BITS) {
+		if (children[0]->type != AST_CONSTANT)
+			log_error("Left operand of to_bits expression is not constant at %s:%d!\n", filename.c_str(), linenum);
+		if (children[1]->type != AST_CONSTANT)
+			log_error("Right operand of to_bits expression is not constant at %s:%d!\n", filename.c_str(), linenum);
+		RTLIL::Const new_value = children[1]->bitsAsConst(children[0]->bitsAsConst().as_int(), children[1]->is_signed);
+		newNode = mkconst_bits(new_value.bits, children[1]->is_signed);
+		goto apply_newNode;
+	}
+
 	// annotate constant ranges
 	if (type == AST_RANGE) {
 		bool old_range_valid = range_valid;