memory_map: Improve start_offset handling.

Fixes #2775.

1 files changed, 100 insertions, 0 deletions

diff --git a/tests/opt/memory_map_offset.ys b/tests/opt/memory_map_offset.ys
new file mode 100644
index 000000000..06969922d
--- /dev/null
+++ b/tests/opt/memory_map_offset.ys
@@ -0,0 +1,100 @@
+read_verilog << EOT
+
+module top(...);
+
+input [3:0] ra;
+input [3:0] wa;
+
+input [15:0] wd;
+output [15:0] rd;
+input en, clk;
+
+reg [15:0] mem[3:9];
+
+always @(posedge clk)
+	if (en)
+		mem[wa] <= wd;
+
+assign rd = mem[ra];
+
+endmodule
+
+EOT
+
+hierarchy -auto-top
+proc
+opt_clean
+memory_map
+
+design -stash gate
+
+read_verilog << EOT
+
+module top(...);
+
+input [3:0] ra;
+input [3:0] wa;
+
+input [15:0] wd;
+output reg [15:0] rd;
+input en, clk;
+
+reg [15:0] \mem[3] ;
+reg [15:0] \mem[4] ;
+reg [15:0] \mem[5] ;
+reg [15:0] \mem[6] ;
+reg [15:0] \mem[7] ;
+reg [15:0] \mem[8] ;
+reg [15:0] \mem[9] ;
+
+always @(posedge clk) begin
+	if (en && wa == 3)
+		\mem[3] <= wd;
+	if (en && wa == 4)
+		\mem[4] <= wd;
+	if (en && wa == 5)
+		\mem[5] <= wd;
+	if (en && wa == 6)
+		\mem[6] <= wd;
+	if (en && wa == 7)
+		\mem[7] <= wd;
+	if (en && wa == 8)
+		\mem[8] <= wd;
+	if (en && wa == 9)
+		\mem[9] <= wd;
+end
+
+always @* begin
+	rd = 16'bx;
+	if (ra == 3)
+		rd = \mem[3] ;
+	if (ra == 4)
+		rd = \mem[4] ;
+	if (ra == 5)
+		rd = \mem[5] ;
+	if (ra == 6)
+		rd = \mem[6] ;
+	if (ra == 7)
+		rd = \mem[7] ;
+	if (ra == 8)
+		rd = \mem[8] ;
+	if (ra == 9)
+		rd = \mem[9] ;
+end
+
+endmodule
+
+EOT
+
+hierarchy -auto-top
+proc
+opt_clean
+
+design -stash gold
+
+design -copy-from gold -as gold A:top
+design -copy-from gate -as gate A:top
+
+equiv_make gold gate equiv
+equiv_induct -undef equiv
+equiv_status -assert equiv