sv: fix size cast internal expression extension

2025-10-30 19:22:31 +00:00 · 2022-01-05 23:33:08 -07:00 · 2022-01-05 23:33:08 -07:00 · 828e85068f
commit 828e85068f
parent 59a7150344
4 changed files with 156 additions and 2 deletions
--- a/2
+++ b/2
@ -18,6 +18,8 @@ Yosys 0.11 .. Yosys 0.12
      expressions and case item expressions
    - Fixed static size casts inadvertently limiting the result width of binary
      operations
+    - Fixed static size casts ignoring expression signedness
+    - Fixed static size casts not extending unbased unsized literals

 * New commands and options
    - Added "-genlib" option to "abc" pass
--- a/frontends/ast/genrtlil.cc
+++ b/frontends/ast/genrtlil.cc
@ -1531,13 +1531,20 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 	// changing the size of signal can be done directly using RTLIL::SigSpec
 	case AST_CAST_SIZE: {
 			RTLIL::SigSpec size = children[0]->genRTLIL();
-			RTLIL::SigSpec sig = children[1]->genRTLIL();
 			if (!size.is_fully_const())
 				log_file_error(filename, location.first_line, "Static cast with non constant expression!\n");
 			int width = size.as_int();
 			if (width <= 0)
 				log_file_error(filename, location.first_line, "Static cast with zero or negative size!\n");
-			sig.extend_u0(width, sign_hint);
+			// determine the *signedness* of the expression
+			int sub_width_hint = -1;
+			bool sub_sign_hint = true;
+			children[1]->detectSignWidth(sub_width_hint, sub_sign_hint);
+			// generate the signal given the *cast's* size and the
+			// *expression's* signedness
+			RTLIL::SigSpec sig = children[1]->genWidthRTLIL(width, sub_sign_hint);
+			// context may effect this node's signedness, but not that of the
+			// casted expression
 			is_signed = sign_hint;
 			return sig;
 		}
--- a/tests/verilog/size_cast.sv
+++ b/tests/verilog/size_cast.sv
@ -0,0 +1,140 @@
+module top;
+    logic L1b0 = 0;
+    logic L1b1 = 1;
+
+    logic signed L1sb0 = 0;
+    logic signed L1sb1 = 1;
+
+    logic [1:0] L2b00 = 0;
+    logic [1:0] L2b01 = 1;
+    logic [1:0] L2b10 = 2;
+    logic [1:0] L2b11 = 3;
+
+    logic signed [1:0] L2sb00 = 0;
+    logic signed [1:0] L2sb01 = 1;
+    logic signed [1:0] L2sb10 = 2;
+    logic signed [1:0] L2sb11 = 3;
+
+    logic y = 1;
+
+    always @* begin
+
+        assert (1'(L1b0  ) == 1'b0);
+        assert (1'(L1b1  ) == 1'b1);
+        assert (1'(L1sb0 ) == 1'b0);
+        assert (1'(L1sb1 ) == 1'b1);
+        assert (1'(L2b00 ) == 1'b0);
+        assert (1'(L2b01 ) == 1'b1);
+        assert (1'(L2b10 ) == 1'b0);
+        assert (1'(L2b11 ) == 1'b1);
+        assert (1'(L2sb00) == 1'b0);
+        assert (1'(L2sb01) == 1'b1);
+        assert (1'(L2sb10) == 1'b0);
+        assert (1'(L2sb11) == 1'b1);
+
+        assert (2'(L1b0  ) == 2'b00);
+        assert (2'(L1b1  ) == 2'b01);
+        assert (2'(L1sb0 ) == 2'b00);
+        assert (2'(L1sb1 ) == 2'b11);
+        assert (2'(L2b00 ) == 2'b00);
+        assert (2'(L2b01 ) == 2'b01);
+        assert (2'(L2b10 ) == 2'b10);
+        assert (2'(L2b11 ) == 2'b11);
+        assert (2'(L2sb00) == 2'b00);
+        assert (2'(L2sb01) == 2'b01);
+        assert (2'(L2sb10) == 2'b10);
+        assert (2'(L2sb11) == 2'b11);
+
+        assert (3'(L1b0  ) == 3'b000);
+        assert (3'(L1b1  ) == 3'b001);
+        assert (3'(L1sb0 ) == 3'b000);
+        assert (3'(L1sb1 ) == 3'b111);
+        assert (3'(L2b00 ) == 3'b000);
+        assert (3'(L2b01 ) == 3'b001);
+        assert (3'(L2b10 ) == 3'b010);
+        assert (3'(L2b11 ) == 3'b011);
+        assert (3'(L2sb00) == 3'b000);
+        assert (3'(L2sb01) == 3'b001);
+        assert (3'(L2sb10) == 3'b110);
+        assert (3'(L2sb11) == 3'b111);
+
+        assert (3'(L1b0   | '1) == 3'b111);
+        assert (3'(L1b1   | '1) == 3'b111);
+        assert (3'(L1sb0  | '1) == 3'b111);
+        assert (3'(L1sb1  | '1) == 3'b111);
+        assert (3'(L2b00  | '1) == 3'b111);
+        assert (3'(L2b01  | '1) == 3'b111);
+        assert (3'(L2b10  | '1) == 3'b111);
+        assert (3'(L2b11  | '1) == 3'b111);
+        assert (3'(L2sb00 | '1) == 3'b111);
+        assert (3'(L2sb01 | '1) == 3'b111);
+        assert (3'(L2sb10 | '1) == 3'b111);
+        assert (3'(L2sb11 | '1) == 3'b111);
+
+        assert (3'(L1b0   | '0) == 3'b000);
+        assert (3'(L1b1   | '0) == 3'b001);
+        assert (3'(L1sb0  | '0) == 3'b000);
+        assert (3'(L1sb1  | '0) == 3'b001);
+        assert (3'(L2b00  | '0) == 3'b000);
+        assert (3'(L2b01  | '0) == 3'b001);
+        assert (3'(L2b10  | '0) == 3'b010);
+        assert (3'(L2b11  | '0) == 3'b011);
+        assert (3'(L2sb00 | '0) == 3'b000);
+        assert (3'(L2sb01 | '0) == 3'b001);
+        assert (3'(L2sb10 | '0) == 3'b010);
+        assert (3'(L2sb11 | '0) == 3'b011);
+
+        assert (3'(y ? L1b0   : '1) == 3'b000);
+        assert (3'(y ? L1b1   : '1) == 3'b001);
+        assert (3'(y ? L1sb0  : '1) == 3'b000);
+        assert (3'(y ? L1sb1  : '1) == 3'b001);
+        assert (3'(y ? L2b00  : '1) == 3'b000);
+        assert (3'(y ? L2b01  : '1) == 3'b001);
+        assert (3'(y ? L2b10  : '1) == 3'b010);
+        assert (3'(y ? L2b11  : '1) == 3'b011);
+        assert (3'(y ? L2sb00 : '1) == 3'b000);
+        assert (3'(y ? L2sb01 : '1) == 3'b001);
+        assert (3'(y ? L2sb10 : '1) == 3'b010);
+        assert (3'(y ? L2sb11 : '1) == 3'b011);
+
+        assert (3'(y ? L1b0   : '0) == 3'b000);
+        assert (3'(y ? L1b1   : '0) == 3'b001);
+        assert (3'(y ? L1sb0  : '0) == 3'b000);
+        assert (3'(y ? L1sb1  : '0) == 3'b001);
+        assert (3'(y ? L2b00  : '0) == 3'b000);
+        assert (3'(y ? L2b01  : '0) == 3'b001);
+        assert (3'(y ? L2b10  : '0) == 3'b010);
+        assert (3'(y ? L2b11  : '0) == 3'b011);
+        assert (3'(y ? L2sb00 : '0) == 3'b000);
+        assert (3'(y ? L2sb01 : '0) == 3'b001);
+        assert (3'(y ? L2sb10 : '0) == 3'b010);
+        assert (3'(y ? L2sb11 : '0) == 3'b011);
+
+        assert (3'(y ? L1b0   : 1'sb0) == 3'b000);
+        assert (3'(y ? L1b1   : 1'sb0) == 3'b001);
+        assert (3'(y ? L1sb0  : 1'sb0) == 3'b000);
+        assert (3'(y ? L1sb1  : 1'sb0) == 3'b111);
+        assert (3'(y ? L2b00  : 1'sb0) == 3'b000);
+        assert (3'(y ? L2b01  : 1'sb0) == 3'b001);
+        assert (3'(y ? L2b10  : 1'sb0) == 3'b010);
+        assert (3'(y ? L2b11  : 1'sb0) == 3'b011);
+        assert (3'(y ? L2sb00 : 1'sb0) == 3'b000);
+        assert (3'(y ? L2sb01 : 1'sb0) == 3'b001);
+        assert (3'(y ? L2sb10 : 1'sb0) == 3'b110);
+        assert (3'(y ? L2sb11 : 1'sb0) == 3'b111);
+
+        assert (3'(y ? L1b0   : 1'sb1) == 3'b000);
+        assert (3'(y ? L1b1   : 1'sb1) == 3'b001);
+        assert (3'(y ? L1sb0  : 1'sb1) == 3'b000);
+        assert (3'(y ? L1sb1  : 1'sb1) == 3'b111);
+        assert (3'(y ? L2b00  : 1'sb1) == 3'b000);
+        assert (3'(y ? L2b01  : 1'sb1) == 3'b001);
+        assert (3'(y ? L2b10  : 1'sb1) == 3'b010);
+        assert (3'(y ? L2b11  : 1'sb1) == 3'b011);
+        assert (3'(y ? L2sb00 : 1'sb1) == 3'b000);
+        assert (3'(y ? L2sb01 : 1'sb1) == 3'b001);
+        assert (3'(y ? L2sb10 : 1'sb1) == 3'b110);
+        assert (3'(y ? L2sb11 : 1'sb1) == 3'b111);
+
+    end
+endmodule
--- a/tests/verilog/size_cast.ys
+++ b/tests/verilog/size_cast.ys
@ -0,0 +1,5 @@
+read_verilog -sv size_cast.sv
+proc
+opt -full
+select -module top
+sat -verify -prove-asserts -show-all