Various improvements in support for generate statements

frontends/ast/ast.cc

@@ -135,6 +135,7 @@ std::string AST::type2str(AstNodeType type)
 	X(AST_GENVAR)
 	X(AST_GENFOR)
 	X(AST_GENIF)
+	X(AST_GENCASE)
 	X(AST_GENBLOCK)
 	X(AST_POSEDGE)
 	X(AST_NEGEDGE)
@@ -700,6 +701,15 @@ RTLIL::Const AstNode::asParaConst()
 	return val;
 }
 
+bool AstNode::asBool()
+{
+	log_assert(type == AST_CONSTANT);
+	for (auto &bit : bits)
+		if (bit == RTLIL::State::S1)
+			return true;
+	return false;
+}
+
 // create a new AstModule from an AST_MODULE AST node
 static AstModule* process_module(AstNode *ast)
 {

frontends/ast/ast.h

@@ -116,6 +116,7 @@ namespace AST
 		AST_GENVAR,
 		AST_GENFOR,
 		AST_GENIF,
+		AST_GENCASE,
 		AST_GENBLOCK,
 
 		AST_POSEDGE,
@@ -218,6 +219,7 @@ namespace AST
 		RTLIL::Const bitsAsConst(int width = -1);
 		RTLIL::Const asAttrConst();
 		RTLIL::Const asParaConst();
+		bool asBool();
 	};
 
 	// process an AST tree (ast must point to an AST_DESIGN node) and generate RTLIL code

frontends/ast/genrtlil.cc

@@ -812,6 +812,7 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 	case AST_GENFOR:
 	case AST_GENBLOCK:
 	case AST_GENIF:
+	case AST_GENCASE:
 		break;
 
 	// remember the parameter, needed for example in techmap

frontends/ast/simplify.cc

@@ -346,7 +346,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		bool did_something_here = true;
 		if ((type == AST_GENFOR || type == AST_FOR) && i >= 3)
 			break;
-		if (type == AST_GENIF && i >= 1)
+		if ((type == AST_GENIF || type == AST_GENCASE) && i >= 1)
 			break;
 		if (type == AST_GENBLOCK)
 			break;
@@ -726,7 +726,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 			// 	dumpAst(f, "verilog-ast> ");
 			log_error("Condition for generate if at %s:%d is not constant!\n", filename.c_str(), linenum);
 		}
-		if (buf->integer != 0) {
+		if (buf->asBool() != 0) {
 			delete buf;
 			buf = children[1]->clone();
 		} else {
@@ -757,6 +757,82 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 		did_something = true;
 	}
 
+	// simplify generate-case blocks
+	if (type == AST_GENCASE && children.size() != 0)
+	{
+		AstNode *buf = children[0]->clone();
+		while (buf->simplify(true, false, false, stage, width_hint, sign_hint)) { }
+		if (buf->type != AST_CONSTANT) {
+			// for (auto f : log_files)
+			// 	dumpAst(f, "verilog-ast> ");
+			log_error("Condition for generate case at %s:%d is not constant!\n", filename.c_str(), linenum);
+		}
+
+		bool ref_signed = buf->is_signed;
+		RTLIL::Const ref_value = buf->bitsAsConst();
+		delete buf;
+
+		AstNode *selected_case = NULL;
+		for (size_t i = 1; i < children.size(); i++)
+		{
+			log_assert(children.at(i)->type == AST_COND);
+
+			AstNode *this_genblock = NULL;
+			for (auto child : children.at(i)->children) {
+				log_assert(this_genblock == NULL);
+				if (child->type == AST_GENBLOCK)
+					this_genblock = child;
+			}
+
+			for (auto child : children.at(i)->children)
+			{
+				if (child->type == AST_DEFAULT) {
+					if (selected_case == NULL)
+						selected_case = this_genblock;
+					continue;
+				}
+				if (child->type == AST_GENBLOCK)
+					continue;
+
+				buf = child->clone();
+				while (buf->simplify(true, false, false, stage, width_hint, sign_hint)) { }
+				if (buf->type != AST_CONSTANT) {
+					// for (auto f : log_files)
+					// 	dumpAst(f, "verilog-ast> ");
+					log_error("Expression in generate case at %s:%d is not constant!\n", filename.c_str(), linenum);
+				}
+
+				if (RTLIL::const_eq(ref_value, buf->bitsAsConst(), ref_signed && buf->is_signed, ref_signed && buf->is_signed, 1).as_bool()) {
+					selected_case = this_genblock;
+					i = children.size();
+					break;
+				}
+			}
+		}
+
+		if (selected_case != NULL)
+		{
+			log_assert(selected_case->type == AST_GENBLOCK);
+			buf = selected_case->clone();
+
+			if (!buf->str.empty()) {
+				std::map<std::string, std::string> name_map;
+				buf->expand_genblock(std::string(), buf->str + ".", name_map);
+			}
+
+			for (size_t i = 0; i < buf->children.size(); i++) {
+				buf->children[i]->simplify(false, false, false, stage, -1, false);
+				current_ast_mod->children.push_back(buf->children[i]);
+			}
+
+			buf->children.clear();
+			delete buf;
+		}
+
+		delete_children();
+		did_something = true;
+	}
+
 	// replace primitives with assignmens
 	if (type == AST_PRIMITIVE)
 	{

frontends/verilog/Makefile.inc

@@ -4,10 +4,12 @@ GENFILES += frontends/verilog/parser.tab.h
 GENFILES += frontends/verilog/parser.output
 GENFILES += frontends/verilog/lexer.cc
 
-frontends/verilog/parser.tab.cc frontends/verilog/parser.tab.h: frontends/verilog/parser.y
+frontends/verilog/parser.tab.cc: frontends/verilog/parser.y
 	bison -d -r all -b frontends/verilog/parser frontends/verilog/parser.y
 	mv frontends/verilog/parser.tab.c frontends/verilog/parser.tab.cc
 
+frontends/verilog/parser.tab.h: frontends/verilog/parser.tab.cc
+
 frontends/verilog/lexer.cc: frontends/verilog/lexer.l
 	flex -o frontends/verilog/lexer.cc frontends/verilog/lexer.l
 

frontends/verilog/parser.y

@@ -887,6 +887,22 @@ case_item:
 		ast_stack.pop_back();
 	};
 
+gen_case_body:
+	gen_case_body gen_case_item |
+	/* empty */;
+
+gen_case_item:
+	{
+		AstNode *node = new AstNode(AST_COND);
+		ast_stack.back()->children.push_back(node);
+		ast_stack.push_back(node);
+	} case_select {
+		case_type_stack.push_back(0);
+	} gen_stmt_or_null {
+		case_type_stack.pop_back();
+		ast_stack.pop_back();
+	};
+
 case_select:
 	case_expr_list ':' |
 	TOK_DEFAULT;
@@ -956,7 +972,6 @@ single_arg:
 
 module_gen_body:
 	module_gen_body gen_stmt |
-	module_gen_body module_body_stmt |
 	/* empty */;
 
 // this production creates the obligatory if-else shift/reduce conflict
@@ -967,7 +982,7 @@ gen_stmt:
 		ast_stack.push_back(node);
 	} simple_behavioral_stmt ';' expr {
 		ast_stack.back()->children.push_back($6);
-	} ';' simple_behavioral_stmt ')' gen_stmt {
+	} ';' simple_behavioral_stmt ')' gen_stmt_block {
 		ast_stack.pop_back();
 	} |
 	TOK_IF '(' expr ')' {
@@ -975,7 +990,15 @@ gen_stmt:
 		ast_stack.back()->children.push_back(node);
 		ast_stack.push_back(node);
 		ast_stack.back()->children.push_back($3);
-	} gen_stmt opt_gen_else {
+	} gen_stmt_block opt_gen_else {
+		ast_stack.pop_back();
+	} |
+	case_type '(' expr ')' {
+		AstNode *node = new AstNode(AST_GENCASE, $3);
+		ast_stack.back()->children.push_back(node);
+		ast_stack.push_back(node);
+	} gen_case_body TOK_ENDCASE {
+		case_type_stack.pop_back();
 		ast_stack.pop_back();
 	} |
 	TOK_BEGIN opt_label {
@@ -989,10 +1012,23 @@ gen_stmt:
 		if ($6 != NULL)
 			delete $6;
 		ast_stack.pop_back();
+	} |
+	module_body_stmt;
+
+gen_stmt_block:
+	{
+		AstNode *node = new AstNode(AST_GENBLOCK);
+		ast_stack.back()->children.push_back(node);
+		ast_stack.push_back(node);
+	} gen_stmt {
+		ast_stack.pop_back();
 	};
 
+gen_stmt_or_null:
+	gen_stmt_block | ';';
+
 opt_gen_else:
-	TOK_ELSE gen_stmt | /* empty */;
+	TOK_ELSE gen_stmt_or_null | /* empty */;
 
 expr:
 	basic_expr {

tests/simple/generate.v

@@ -65,3 +65,30 @@ end
 
 endmodule
 
+// ------------------------------------------
+
+module test3(a, b, sel, y, z);
+
+input [3:0] a, b;
+input sel;
+output [3:0] y, z;
+
+genvar i;
+generate
+	for (i=0; i < 2; i=i+1)
+		assign y[i] = sel ? a[i] : b[i], z[i] = sel ? b[i] : a[i];
+	for (i=0; i < 2; i=i+1) begin
+		if (i == 0)
+			assign y[2] = sel ? a[2] : b[2];
+		else
+			assign z[2] = sel ? a[2] : b[2];
+		case (i)
+		default:
+			assign z[3] = sel ? a[3] : b[3];
+		0:
+			assign y[3] = sel ? a[3] : b[3];
+		endcase
+	end
+endgenerate
+
+endmodule