From 882b3108972028d730fdb25e7f51f767a894dda7 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Sun, 13 Dec 2020 16:23:59 -0500
Subject: [PATCH] Fix little endian packed array counting (#2499).

---
 Changes                                 |  6 ++-
 src/V3WidthSel.cpp                      | 10 ++--
 test_regress/t/t_array_packed_endian.pl | 21 ++++++++
 test_regress/t/t_array_packed_endian.v  | 71 +++++++++++++++++++++++++
 4 files changed, 100 insertions(+), 8 deletions(-)
 create mode 100755 test_regress/t/t_array_packed_endian.pl
 create mode 100644 test_regress/t/t_array_packed_endian.v

diff --git a/Changes b/Changes
index d90693a1c..2ed4937f2 100644
--- a/Changes
+++ b/Changes
@@ -19,12 +19,14 @@ The contributors that suggested a given feature are shown in []. Thanks!
 
 ****  Fix DPI open array handling issues.
 
+****  Fix error when dotted refers to missing module (#2095). [Alexander Grobman]
+
+****  Fix little endian packed array counting (#2499). [phantom-killua]
+
 ****  Fix showing reference locations for BLKANDNBLK (#2170). [Yuri Victorovich]
 
 ****  Fix genblk naming to match IEEE (#2686). [tinshark]
 
-****  Fix error when dotted refers to missing module (#2095). [Alexander Grobman]
-
 
 * Verilator 4.106 2020-12-02
 
diff --git a/src/V3WidthSel.cpp b/src/V3WidthSel.cpp
index 0b2455c63..9649bd43f 100644
--- a/src/V3WidthSel.cpp
+++ b/src/V3WidthSel.cpp
@@ -225,12 +225,10 @@ private:
         } else if (AstPackArrayDType* adtypep = VN_CAST(ddtypep, PackArrayDType)) {
             // SELBIT(array, index) -> SEL(array, index*width-of-subindex, width-of-subindex)
             AstNode* subp = rhsp;
-            if (fromRange.lo() != 0 || fromRange.hi() < 0) {
-                if (fromRange.littleEndian()) {
-                    subp = newSubNeg(fromRange.hi(), subp);
-                } else {
-                    subp = newSubNeg(subp, fromRange.lo());
-                }
+            if (fromRange.littleEndian()) {
+                subp = newSubNeg(fromRange.hi(), subp);
+            } else {
+                subp = newSubNeg(subp, fromRange.lo());
             }
             UASSERT_OBJ(!(!fromRange.elements() || (adtypep->width() % fromRange.elements()) != 0),
                         adtypep,
diff --git a/test_regress/t/t_array_packed_endian.pl b/test_regress/t/t_array_packed_endian.pl
new file mode 100755
index 000000000..9a15dd2cc
--- /dev/null
+++ b/test_regress/t/t_array_packed_endian.pl
@@ -0,0 +1,21 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2019 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(simulator => 1);
+
+compile(
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_array_packed_endian.v b/test_regress/t/t_array_packed_endian.v
new file mode 100644
index 000000000..6af307eea
--- /dev/null
+++ b/test_regress/t/t_array_packed_endian.v
@@ -0,0 +1,71 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2020 Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+`define stop $stop
+`define checkh(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d:  got='h%x exp='h%x\n", `__FILE__,`__LINE__, (gotv), (expv)); `stop; end while(0)
+
+typedef struct packed {
+   logic [7:0] a;
+} tb_t;
+
+typedef struct packed {
+   // verilator lint_off LITENDIAN
+   logic [0:7] a;
+   // verilator lint_on LITENDIAN
+} tl_t;
+
+typedef struct packed {
+   logic [7:0] bb;
+   // verilator lint_off LITENDIAN
+   tb_t [0:1] cbl;
+   tb_t [1:0] cbb;
+   tl_t [0:1] cll;
+   tl_t [1:0] clb;
+   logic [0:7] dl;
+   // verilator lint_on LITENDIAN
+} t2;
+
+module t;
+   t2 t;
+   initial begin
+      t = 80'hcd_1f2f3f4f_5f6f7f8f_c2;
+      `checkh(t.bb, 8'hcd);
+      `checkh(t.cbl[0].a, 8'h1f);
+      `checkh(t.cbl[1].a, 8'h2f);
+      `checkh(t.cbb[0].a, 8'h4f);
+      `checkh(t.cbb[1].a, 8'h3f);
+      `checkh(t.cll[0].a, 8'h5f);
+      `checkh(t.cll[1].a, 8'h6f);
+      `checkh(t.clb[0].a, 8'h8f);
+      `checkh(t.clb[1].a, 8'h7f);
+      `checkh(t.dl, 8'hc2);
+
+      t = '0;
+      t.bb = 8'h13;
+      t.cbl[0].a = 8'hac;
+      t.cbl[1].a = 8'had;
+      t.cbb[0].a = 8'hae;
+      t.cbb[1].a = 8'haf;
+      t.cll[0].a = 8'hbc;
+      t.cll[1].a = 8'hbd;
+      t.clb[0].a = 8'hbe;
+      t.clb[1].a = 8'hbf;
+      t.dl = 8'h31;
+      `checkh(t, 80'h13_acadafae_bcbdbfbe_31);
+
+      t = '0;
+      t.bb[7] = 1'b1;
+      t.cbl[1].a[1] = 1'b1;
+      t.cbb[1].a[2] = 1'b1;
+      t.cll[1].a[3] = 1'b1;
+      t.clb[1].a[4] = 1'b1;
+      t.dl[7] = 1'b1;
+      `checkh(t, 80'h80_0002040000100800_01);
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule