verilog: fix sizing of constant args for tasks/functions

- Simplify synthetic localparams for normal calls to update their width
    - This step was inadvertently removed alongside `added_mod_children`
- Support redeclaration of constant function arguments
    - `eval_const_function` never correctly handled this, but the issue
      was not exposed in the existing tests until the recent change to
      always attempt constant function evaluation when all-const args
      are used
- Check asserts in const_arg_loop and const_func tests
- Add coverage for width mismatch error cases

frontends/ast/ast.h

@@ -263,7 +263,13 @@ namespace AST
 		bool detect_latch(const std::string &var);
 
 		// additional functionality for evaluating constant functions
-		struct varinfo_t { RTLIL::Const val; int offset; bool is_signed; };
+		struct varinfo_t {
+			RTLIL::Const val;
+			int offset;
+			bool is_signed;
+			AstNode *arg = nullptr;
+			bool explicitly_sized;
+		};
 		bool has_const_only_constructs();
 		bool replace_variables(std::map<std::string, varinfo_t> &variables, AstNode *fcall, bool must_succeed);
 		AstNode *eval_const_function(AstNode *fcall, bool must_succeed);

frontends/ast/simplify.cc

@@ -3376,6 +3376,8 @@ skip_dynamic_range_lvalue_expansion:;
 								range->children.push_back(mkconst_int(0, true));
 							}
 						}
+						// updates the sizing
+						while (wire->simplify(true, false, false, 1, -1, false, false)) { }
 						continue;
 					}
 					AstNode *wire_id = new AstNode(AST_IDENTIFIER);
@@ -4591,17 +4593,29 @@ AstNode *AstNode::eval_const_function(AstNode *fcall, bool must_succeed)
 				log_file_error(stmt->filename, stmt->location.first_line, "Can't determine size of variable %s\n%s:%d.%d-%d.%d: ... called from here.\n",
 						stmt->str.c_str(), fcall->filename.c_str(), fcall->location.first_line, fcall->location.first_column, fcall->location.last_line, fcall->location.last_column);
 			}
-			variables[stmt->str].val = RTLIL::Const(RTLIL::State::Sx, abs(stmt->range_left - stmt->range_right)+1);
-			variables[stmt->str].offset = min(stmt->range_left, stmt->range_right);
-			variables[stmt->str].is_signed = stmt->is_signed;
+			AstNode::varinfo_t &variable = variables[stmt->str];
+			int width = abs(stmt->range_left - stmt->range_right) + 1;
+			// if this variable has already been declared as an input, check the
+			// sizes match if it already had an explicit size
+			if (variable.arg && variable.explicitly_sized && variable.val.size() != width) {
+				log_file_error(filename, location.first_line, "Incompatible re-declaration of constant function wire %s.\n", stmt->str.c_str());
+			}
+			variable.val = RTLIL::Const(RTLIL::State::Sx, width);
+			variable.offset = min(stmt->range_left, stmt->range_right);
+			variable.is_signed = stmt->is_signed;
+			variable.explicitly_sized = stmt->children.size() &&
+				stmt->children.back()->type == AST_RANGE;
+			// identify the argument corresponding to this wire, if applicable
 			if (stmt->is_input && argidx < fcall->children.size()) {
-				int width = variables[stmt->str].val.bits.size();
-				auto* arg_node = fcall->children.at(argidx++);
-				if (arg_node->type == AST_CONSTANT) {
-					variables[stmt->str].val = arg_node->bitsAsConst(width);
+				variable.arg = fcall->children.at(argidx++);
+			}
+			// load the constant arg's value into this variable
+			if (variable.arg) {
+				if (variable.arg->type == AST_CONSTANT) {
+					variable.val = variable.arg->bitsAsConst(width);
 				} else {
-					log_assert(arg_node->type == AST_REALVALUE);
-					variables[stmt->str].val = arg_node->realAsConst(width);
+					log_assert(variable.arg->type == AST_REALVALUE);
+					variable.val = variable.arg->realAsConst(width);
 				}
 			}
 			current_scope[stmt->str] = stmt;

tests/various/const_arg_loop.sv

@@ -20,11 +20,11 @@ module top;
 	endfunction
 
 	function automatic [31:0] operation2;
-		input [4:0] var;
+		input [4:0] inp;
 		input integer num;
 		begin
-			var[0] = var[0] ^ 1;
-			operation2 = num * var;
+			inp[0] = inp[0] ^ 1;
+			operation2 = num * inp;
 		end
 	endfunction
 
@@ -79,15 +79,14 @@ module top;
 	wire [31:0] x5;
 	assign x5 = operation5(64);
 
-// `define VERIFY
-`ifdef VERIFY
-    assert property (a == 2);
-    assert property (A == 3);
-    assert property (x1 == 16);
-    assert property (x1b == 16);
-    assert property (x2 == 4);
-    assert property (x3 == 16);
-    assert property (x4 == a << 1);
-    assert property (x5 == 64);
-`endif
+	always_comb begin
+		assert(a == 2);
+		assert(A == 3);
+		assert(x1 == 16);
+		assert(x1b == 16);
+		assert(x2 == 4);
+		assert(x3 == 16);
+		assert(x4 == a << 1);
+		assert(x5 == 64);
+	end
 endmodule

tests/various/const_arg_loop.ys

@@ -1 +1,6 @@
-read_verilog const_arg_loop.v
+read_verilog -sv const_arg_loop.sv
+hierarchy
+proc
+opt -full
+select -module top
+sat -verify -seq 1 -tempinduct -prove-asserts -show-all

tests/various/const_func.sv

@@ -62,26 +62,25 @@ module top(out);
     localparam signed Y = $floor(W / X);
     localparam signed Z = negate($floor(W / X));
 
-// `define VERIFY
-`ifdef VERIFY
-    assert property (a1 == 0);
-    assert property (a2 == 0);
-    assert property (a3 == "BAR");
-    assert property (a4 == 0);
-    assert property (b1 == "FOO");
-    assert property (b2 == "FOO");
-    assert property (b3 == 0);
-    assert property (b4 == "HI");
-    assert property (c1 == 1);
-    assert property (c2 == 1);
-    assert property (c3 == 0);
-    assert property (c4 == 0);
-    assert property (d1 == 0);
-    assert property (d2 == 0);
-    assert property (d3 == 1);
-    assert property (d4 == 1);
+    always_comb begin
+        assert(a1 == 0);
+        assert(a2 == 0);
+        assert(a3 == "BAR");
+        assert(a4 == 0);
+        assert(b1 == "FOO");
+        assert(b2 == "FOO");
+        assert(b3 == 0);
+        assert(b4 == "HI");
+        assert(c1 == 1);
+        assert(c2 == 1);
+        assert(c3 == 0);
+        assert(c4 == 0);
+        assert(d1 == 0);
+        assert(d2 == 0);
+        assert(d3 == 1);
+        assert(d4 == 1);
 
-    assert property (Y == 3);
-    assert property (Z == ~3);
-`endif
+        assert(Y == 3);
+        assert(Z == ~3);
+    end
 endmodule

tests/various/const_func.ys

@@ -1 +1,7 @@
-read_verilog const_func.v
+read_verilog -sv const_func.sv
+hierarchy
+proc
+flatten
+opt -full
+select -module top
+sat -verify -seq 1 -tempinduct -prove-asserts -show-all

tests/verilog/func_arg_mismatch_1.ys

@@ -0,0 +1,12 @@
+logger -expect error "Incompatible re-declaration of wire" 1
+read_verilog -sv <<EOT
+module top;
+    function automatic integer f;
+        input [0:0] inp;
+        integer inp;
+        f = inp;
+    endfunction
+    integer x, y;
+    initial x = f(y);
+endmodule
+EOT

tests/verilog/func_arg_mismatch_2.ys

@@ -0,0 +1,12 @@
+logger -expect error "Incompatible re-declaration of constant function wire" 1
+read_verilog -sv <<EOT
+module top;
+    function automatic integer f;
+        input [0:0] inp;
+        integer inp;
+        f = inp;
+    endfunction
+    integer x;
+    initial x = f(0);
+endmodule
+EOT

tests/verilog/func_arg_mismatch_3.ys

@@ -0,0 +1,12 @@
+logger -expect error "Incompatible re-declaration of wire" 1
+read_verilog -sv <<EOT
+module top;
+    function automatic integer f;
+        input [1:0] inp;
+        integer inp;
+        f = inp;
+    endfunction
+    integer x, y;
+    initial x = f(y);
+endmodule
+EOT

tests/verilog/func_arg_mismatch_4.ys

@@ -0,0 +1,12 @@
+logger -expect error "Incompatible re-declaration of constant function wire" 1
+read_verilog -sv <<EOT
+module top;
+    function automatic integer f;
+        input [1:0] inp;
+        integer inp;
+        f = inp;
+    endfunction
+    integer x;
+    initial x = f(0);
+endmodule
+EOT