Add regression tests for oob write to function return value

Check that partial and fully out-of-bound writes to a function's return
value are handled correctly. Check this for both 4-state and 2-state
vectors.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>

ivtest/ivltests/pv_wr_fn_vec2.v

@@ -0,0 +1,99 @@
+// Check that blocking partial writes to a 2-state vector function return value
+// are correctly handled.
+
+module test;
+
+  reg failed = 1'b0;
+
+  `define check(val, exp) \
+    if (exp !== val) begin \
+      $display("FAILED. Got %b, expected %b.", val, exp); \
+      failed = 1'b1; \
+    end
+
+  function bit [3:0] f;
+    integer i;
+
+    // Immediate index
+
+    // Within bounds
+    f = 'h0;
+    f[2:1] = 2'b10;
+    `check(f, 4'b0100)
+
+    // Partially oob at high and low side
+    f = 'h0;
+    f[4:-1] = 6'b101010;
+    `check(f, 4'b0101)
+    // Partially oob at low side
+    f = 'h0;
+    f[0:-1] = 2'b10;
+    `check(f, 4'b0001)
+    // Partially oob at high side
+    f = 'h0;
+    f[4:3] = 2'b01;
+    `check(f, 4'b1000)
+    // Fully oob at low side
+    f = 'h0;
+    f[-1:-2] = 2'b11;
+    `check(f, 4'b0000)
+    // Fully oob at high side
+    f = 'h0;
+    f[6:5] = 2'b11;
+    `check(f, 4'b0000)
+
+    // Variable index
+
+    // Within bounds
+    i = 1;
+    f = 'h0;
+    f[i+:2] = 2'b10;
+    `check(f, 4'b0100)
+
+    // Partially oob at high and low side
+    i = -1;
+    f = 'h0;
+    f[i+:6] = 6'b101010;
+    `check(f, 4'b0101)
+
+    // Partially oob at low side
+    i = -1;
+    f = 'h0;
+    f[i+:2] = 2'b10;
+    `check(f, 4'b0001)
+
+    // Partially oob at high side
+    i = 3;
+    f = 'h0;
+    f[i+:2] = 2'b01;
+    `check(f, 4'b1000)
+
+    // Fully oob at low side
+    i = -2;
+    f = 'h0;
+    f[i+:2] = 2'b11;
+    `check(f, 4'b0000)
+
+    // Fully oob at high side
+    i = 5;
+    f = 'h0;
+    f[i+:2] = 2'b11;
+    `check(f, 4'b0000)
+
+    // Undefined index
+    i = 'hx;
+    f = 'h0;
+    f[i+:2] = 2'b11;
+    `check(f, 4'b0000)
+  endfunction
+
+  initial begin
+    bit [3:0] x;
+    x = f();
+
+    if (!failed) begin
+      $display("PASSED");
+    end
+  end
+
+endmodule

ivtest/ivltests/pv_wr_fn_vec4.v

@@ -0,0 +1,106 @@
+// Check that blocking partial writes to a 4-state vector function return value
+// are correctly handled.
+
+module test;
+
+  reg failed = 1'b0;
+
+  `define check(val, exp) \
+    if (exp !== val) begin \
+      $display("FAILED. Got %b, expected %b.", val, exp); \
+      failed = 1'b1; \
+    end
+
+  integer i;
+
+  function reg [3:0] f(input reg unused);
+  begin
+    // Immediate index
+
+    // Within bounds
+    f = 'hx;
+    f[2:1] = 2'b10;
+    `check(f, 4'bx10x)
+
+    // Partially oob at high and low side
+    f = 'hx;
+    f[4:-1] = 6'b101010;
+    `check(f, 4'b0101)
+
+    // Partially oob at low side
+    f = 'hx;
+    f[0:-1] = 2'b10;
+    `check(f, 4'bxxx1)
+
+    // Partially oob at high side
+    f = 'hx;
+    f[4:3] = 2'b01;
+    `check(f, 4'b1xxx)
+
+    // Fully oob at low side
+    f = 'hx;
+    f[-1:-2] = 2'b11;
+    `check(f, 4'bxxxx)
+
+    // Fully oob at high side
+    f = 'hx;
+    f[6:5] = 2'b11;
+    `check(f, 4'bxxxx)
+
+    // Variable index
+
+    // Within bounds
+    i = 1;
+    f = 'hx;
+    f[i+:2] = 2'b10;
+    `check(f, 4'bx10x)
+
+    // Partially oob at high and low side
+    i = -1;
+    f = 'hx;
+    f[i+:6] = 6'b101010;
+    `check(f, 4'b0101)
+
+    // Partially oob at low side
+    i = -1;
+    f = 'hx;
+    f[i+:2] = 2'b10;
+    `check(f, 4'bxxx1)
+
+    // Partially oob at high side
+    i = 3;
+    f = 'hx;
+    f[i+:2] = 2'b01;
+    `check(f, 4'b1xxx)
+
+    // Fully oob at low side
+    i = -2;
+    f = 'hx;
+    f[i+:2] = 2'b11;
+    `check(f, 4'bxxxx)
+
+    // Fully oob at high side
+    i = 5;
+    f = 'hx;
+    f[i+:2] = 2'b11;
+    `check(f, 4'bxxxx)
+
+    // Undefined index
+    i = 'hx;
+    f = 'hx;
+    f[i+:2] = 2'b11;
+    `check(f, 4'bxxxx)
+  end
+  endfunction
+
+  reg [3:0] x;
+
+  initial begin
+    x = f(1'b0);
+
+    if (!failed) begin
+      $display("PASSED");
+    end
+  end
+
+endmodule

ivtest/regress-vvp.list

@@ -31,6 +31,8 @@ pr1388974			vvp_tests/pr1388974.json
 pr1388974-vlog95		vvp_tests/pr1388974-vlog95.json
 pr903				vvp_tests/pr903.json
 pr903-vlog95			vvp_tests/pr903-vlog95.json
+pv_wr_fn_vec2			vvp_tests/pv_wr_fn_vec2.json
+pv_wr_fn_vec4			vvp_tests/pv_wr_fn_vec4.json
 struct_packed_write_read	vvp_tests/struct_packed_write_read.json
 struct_packed_write_read2	vvp_tests/struct_packed_write_read2.json
 sv_array_cassign6		vvp_tests/sv_array_cassign6.json

ivtest/vvp_tests/pv_wr_fn_vec2.json

@@ -0,0 +1,5 @@
+{
+    "type"          : "normal",
+    "source"        : "pv_wr_fn_vec2.v",
+    "iverilog-args" : [ "-g2009" ]
+}

ivtest/vvp_tests/pv_wr_fn_vec4.json

@@ -0,0 +1,4 @@
+{
+    "type"          : "normal",
+    "source"        : "pv_wr_fn_vec4.v"
+}