From 2a17b06fc447a15164a9ab90780df71869e299a3 Mon Sep 17 00:00:00 2001
From: Lars-Peter Clausen <lars@metafoo.de>
Date: Mon, 26 Jun 2023 06:06:07 -0700
Subject: [PATCH] Add regression test for bit select on multi-dimensional
 signed packed array

Check that element and bit select on multi-dimensional signed packed arrays
are unsigned.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
---
 ivtest/ivltests/bitsel11.v     | 63 ++++++++++++++++++++++++++++++++++
 ivtest/regress-vvp.list        |  1 +
 ivtest/vvp_tests/bitsel11.json |  5 +++
 3 files changed, 69 insertions(+)
 create mode 100644 ivtest/ivltests/bitsel11.v
 create mode 100644 ivtest/vvp_tests/bitsel11.json

diff --git a/ivtest/ivltests/bitsel11.v b/ivtest/ivltests/bitsel11.v
new file mode 100644
index 000000000..74196cc79
--- /dev/null
+++ b/ivtest/ivltests/bitsel11.v
@@ -0,0 +1,63 @@
+// Check that element and bit select on multi-dimensional signed packed arrays
+// are unsigned.
+
+module test;
+
+  bit failed = 1'b0;
+
+`define check(val, exp) do begin \
+    if (val !== exp) begin \
+      $display("FAILED(%0d): Expected `%b`, got `%b`.", `__LINE__, exp, val); \
+      failed = 1'b1; \
+    end \
+  end while (0)
+
+  reg signed [3:0][3:0] arr;
+  integer idx;
+  reg [7:0] x;
+  reg [3:0] y;
+  reg [31:0] z;
+
+  initial begin
+    // Set lowest element to all 1
+    arr = 16'hffff;
+
+    // Elements of a signed packed array are unsigned, no sign extensions
+    idx = 0;
+    x = arr[idx];
+    `check(x, 8'h0f);
+
+    // Out-of-bounds
+    idx = -1;
+    x = arr[idx];
+    `check(x, 8'h0x);
+
+    // Undefined
+    idx = 'bx;
+    x = arr[idx];
+    `check(x, 8'h0x);
+
+    // Bit selects on a signed packed array are unsigned, no sign extensions
+    idx = 0;
+    y = arr[0][idx];
+    `check(y, 4'b0001);
+
+    // Out-of-bounds
+    idx = -1;
+    y = arr[0][idx];
+    `check(y, 4'b000x);
+
+    // Undefined
+    idx = 'bx;
+    y = arr[0][idx];
+    `check(y, 4'b000x);
+
+    // The array as a primary is signed, sign extension
+    z = arr;
+    `check(z, 32'hffffffff);
+
+    if (!failed) begin
+      $display("PASSED");
+    end
+  end
+endmodule
diff --git a/ivtest/regress-vvp.list b/ivtest/regress-vvp.list
index 8ab931c1a..6fe3647ff 100644
--- a/ivtest/regress-vvp.list
+++ b/ivtest/regress-vvp.list
@@ -3,6 +3,7 @@
 # describes the test.
 
 array_packed_write_read		vvp_tests/array_packed_write_read.json
+bitsel11			vvp_tests/bitsel11.json
 br_gh13a			vvp_tests/br_gh13a.json
 br_gh13a-vlog95			vvp_tests/br_gh13a-vlog95.json
 br_gh939			vvp_tests/br_gh939.json
diff --git a/ivtest/vvp_tests/bitsel11.json b/ivtest/vvp_tests/bitsel11.json
new file mode 100644
index 000000000..ecfa7c265
--- /dev/null
+++ b/ivtest/vvp_tests/bitsel11.json
@@ -0,0 +1,5 @@
+{
+    "type"          : "normal",
+    "source"        : "bitsel11.v",
+    "iverilog-args" : [ "-g2005-sv" ]
+}