3 files changed, 68 insertions, 0 deletions
diff --git a/tests/various/constmsk_test.v b/tests/various/constmsk_test.v
new file mode 100644
index 00000000..0d0e58fe
--- /dev/null
+++ b/tests/various/constmsk_test.v
@@ -0,0 +1,4 @@
+module test(input [3:0] A, output [3:0] Y1, Y2);
+    assign Y1 = |{A[3], 1'b0, A[1]};
+    assign Y2 = |{A[2], 1'b1, A[0]};
+endmodule
diff --git a/tests/various/constmsk_test.ys b/tests/various/constmsk_test.ys
new file mode 100644
index 00000000..ce36efc3
--- /dev/null
+++ b/tests/various/constmsk_test.ys
@@ -0,0 +1,15 @@
+read_verilog constmsk_test.v
+
+copy test gold
+rename test gate
+
+cd gate
+techmap -map constmsk_testmap.v;;
+cd ..
+
+select -assert-count 2 gold/r:A_WIDTH=3
+select -assert-count 1 gate/r:A_WIDTH=2
+select -assert-count 1 gate/c:*
+
+miter -equiv -flatten gold gate miter
+sat -verify -prove trigger 0 miter
diff --git a/tests/various/constmsk_testmap.v b/tests/various/constmsk_testmap.v
new file mode 100644
index 00000000..fab1b1bb
--- /dev/null
+++ b/tests/various/constmsk_testmap.v
@@ -0,0 +1,49 @@
+(* techmap_celltype = "$reduce_or" *)
+module my_opt_reduce_or(...);
+    parameter A_SIGNED = 0;
+    parameter A_WIDTH = 1;
+    parameter Y_WIDTH = 1;
+
+    input [A_WIDTH-1:0] A;
+    output reg [Y_WIDTH-1:0] Y;
+
+    parameter _TECHMAP_CONSTMSK_A_ = 0;
+    parameter _TECHMAP_CONSTVAL_A_ = 0;
+
+    wire _TECHMAP_FAIL_ = count_nonconst_bits() == A_WIDTH;
+    wire [1024:0] _TECHMAP_DO_ = "proc;;";
+
+    function integer count_nonconst_bits;
+        integer i;
+        begin
+            count_nonconst_bits = 0;
+            for (i = 0; i < A_WIDTH; i=i+1)
+                if (!_TECHMAP_CONSTMSK_A_[i])
+                    count_nonconst_bits = count_nonconst_bits+1;
+        end
+    endfunction
+
+    function has_const_one;
+        integer i;
+        begin
+            has_const_one = 0;
+            for (i = 0; i < A_WIDTH; i=i+1)
+                if (_TECHMAP_CONSTMSK_A_[i] && _TECHMAP_CONSTVAL_A_[i] === 1'b1)
+                    has_const_one = 1;
+        end
+    endfunction
+
+    integer i;
+    reg [count_nonconst_bits()-1:0] tmp;
+
+    always @* begin
+        if (has_const_one()) begin
+            Y = 1;
+        end else begin
+            for (i = 0; i < A_WIDTH; i=i+1)
+                if (!_TECHMAP_CONSTMSK_A_[i])
+                    tmp = {A[i], tmp[count_nonconst_bits()-1:1]};
+            Y = |tmp;
+        end
+    end
+endmodule