From: Zachary Snow <zach@zachjs.com>
Date: Sun, 6 Dec 2020 01:56:18 +0000 (-0700)
Subject: Fix constants bound to single bit arguments (fixes #2383)
X-Git-Tag: working-ls180~149^2
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=8206546c45d8fe74ac291a548fa372d1bd98f966;p=yosys.git

Fix constants bound to single bit arguments (fixes #2383)
---

diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index fb6623f02..8cd459913 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -3337,6 +3337,14 @@ skip_dynamic_range_lvalue_expansion:;
 						wire->type = AST_LOCALPARAM;
 						wire->attributes.erase(ID::nosync);
 						wire->children.insert(wire->children.begin(), arg->clone());
+						// args without a range implicitly have width 1
+						if (wire->children.back()->type != AST_RANGE) {
+							AstNode* range = new AstNode();
+							range->type = AST_RANGE;
+							wire->children.push_back(range);
+							range->children.push_back(mkconst_int(0, true));
+							range->children.push_back(mkconst_int(0, true));
+						}
 						continue;
 					}
 					AstNode *wire_id = new AstNode(AST_IDENTIFIER);
diff --git a/tests/various/const_arg_loop.v b/tests/various/const_arg_loop.v
index 3bfff4acd..567bccc25 100644
--- a/tests/various/const_arg_loop.v
+++ b/tests/various/const_arg_loop.v
@@ -39,6 +39,12 @@ module top;
 		end
 	endfunction
 
+	function automatic [16:0] operation4;
+		input [15:0] a;
+		input b;
+		operation4 = {a, b};
+	endfunction
+
 	wire [31:0] a;
 	assign a = 2;
 
@@ -53,6 +59,9 @@ module top;
 	wire [31:0] x3;
 	assign x3 = operation3(A, a);
 
+	wire [16:0] x4;
+	assign x4 = operation4(a[15:0], 0);
+
 // `define VERIFY
 `ifdef VERIFY
     assert property (a == 2);
@@ -60,5 +69,6 @@ module top;
     assert property (x1 == 16);
     assert property (x2 == 4);
     assert property (x3 == 16);
+    assert property (x4 == a << 1);
 `endif
 endmodule