From ebd574474c838d054defea691a5fbc8589a14beb Mon Sep 17 00:00:00 2001
From: Lars-Peter Clausen <lars@metafoo.de>
Date: Sat, 4 Jun 2022 10:26:38 +0200
Subject: [PATCH] Add regression test for non-blocking event control to
 concatenation

Check that a non-blocking event control assignment works as expected to a
lvalue concatenation. All values that are part of the concatenation should
only be assigned after the event triggers.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
---
 ivtest/ivltests/nb_ec_concat.v | 104 +++++++++++++++++++++++++++++++++
 ivtest/regress-vlg.list        |   1 +
 2 files changed, 105 insertions(+)
 create mode 100644 ivtest/ivltests/nb_ec_concat.v

diff --git a/ivtest/ivltests/nb_ec_concat.v b/ivtest/ivltests/nb_ec_concat.v
new file mode 100644
index 000000000..a27ae3a99
--- /dev/null
+++ b/ivtest/ivltests/nb_ec_concat.v
@@ -0,0 +1,104 @@
+// Check that non-blocking event control assignments to concatanations work as
+// expected.
+
+module test;
+  reg failed = 1'b0;
+
+  `define check(val, exp) \
+    if (val !== exp) begin \
+      $display("FAILED. %s: expected %b, got %b.", `"val`", exp, val); \
+      failed = 1'b1; \
+    end
+
+  reg [3:0] x;
+  reg [3:0] y;
+  reg [3:0] z[1:0];
+
+  integer i = 0;
+  event e;
+
+  initial begin
+    // Test all of
+    //  * vector
+    //  * vector part select
+    //  * array element
+    //  * array element part
+
+    // Immediate index
+    {z[1][1:0],z[0],y[1:0],x} <= @e 12'h5a5;
+    #1
+    // Assignment must not occur until the event is triggered
+    `check(z[1], 4'bxxxx)
+    `check(z[0], 4'bxxxx)
+    `check(y, 4'bxxxx)
+    `check(x, 4'bxxxx)
+
+    ->e;
+    `check(z[1], 4'bxx01);
+    `check(z[0], 4'b0110);
+    `check(y, 4'bxx10);
+    `check(x, 4'b0101);
+
+    x = 4'hx;
+    y = 4'hx;
+    z[0] = 4'hx;
+    z[1] = 4'hx;
+
+    // Immediate index reverse order
+    {x,y[1:0],z[0],z[1][1:0]} <= @e 12'ha5a;
+    #1
+    `check(z[1], 4'bxxxx)
+    `check(z[0], 4'bxxxx)
+    `check(y, 4'bxxxx)
+    `check(x, 4'bxxxx)
+
+    ->e;
+    `check(z[1], 4'bxx10);
+    `check(z[0], 4'b0110);
+    `check(y, 4'bxx01);
+    `check(x, 4'b1010);
+
+    x = 4'hx;
+    y = 4'hx;
+    z[0] = 4'hx;
+    z[1] = 4'hx;
+
+    // Variable index
+    {z[i+1][i+:2],z[i],y[i+:2],x} <= @e 12'h5a5;
+    #1
+    `check(z[1], 4'bxxxx)
+    `check(z[0], 4'bxxxx)
+    `check(y, 4'bxxxx)
+    `check(x, 4'bxxxx)
+
+    ->e;
+    `check(z[1], 4'bxx01);
+    `check(z[0], 4'b0110);
+    `check(y, 4'bxx10);
+    `check(x, 4'b0101);
+
+    x = 4'hx;
+    y = 4'hx;
+    z[0] = 4'hx;
+    z[1] = 4'hx;
+
+    // Variable index reverse order
+    {x,y[i+:2],z[i],z[i+1][i+:2]} <= @e 12'ha5a;
+    #1
+    `check(z[1], 4'bxxxx)
+    `check(z[0], 4'bxxxx)
+    `check(y, 4'bxxxx)
+    `check(x, 4'bxxxx)
+
+    ->e;
+    `check(z[1], 4'bxx10);
+    `check(z[0], 4'b0110);
+    `check(y, 4'bxx01);
+    `check(x, 4'b1010);
+
+    if (!failed) begin
+      $display("PASSED");
+    end
+  end
+
+endmodule
diff --git a/ivtest/regress-vlg.list b/ivtest/regress-vlg.list
index 9a15545ac..74b1c5ed1 100644
--- a/ivtest/regress-vlg.list
+++ b/ivtest/regress-vlg.list
@@ -676,6 +676,7 @@ muxtest			normal			ivltests # Validates that X sel and inputs same, output not X
 named_event_no_edges	CE			ivltests
 nb_assign		normal			ivltests
 nb_delay		normal			ivltests
+nb_ec_concat		normal			ivltests
 nblkorder		normal			ivltests # Validates Non-blocking order determinism
 negative_genvar		normal			ivltests
 negvalue		normal			ivltests gold=negvalue.gold