Added correct handling of $memwr priority

frontends/ast/genrtlil.cc

@@ -1271,6 +1271,8 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
 
 			cell->parameters["\\CLK_ENABLE"] = RTLIL::Const(0);
 			cell->parameters["\\CLK_POLARITY"] = RTLIL::Const(0);
+
+			cell->parameters["\\PRIORITY"] = RTLIL::Const(RTLIL::autoidx-1);
 		}
 		break;
 

kernel/rtlil.cc

@@ -567,6 +567,7 @@ namespace {
 				param("\\MEMID");
 				param("\\CLK_ENABLE");
 				param("\\CLK_POLARITY");
+				param("\\PRIORITY");
 				port("\\CLK", 1);
 				port("\\EN", 1);
 				port("\\ADDR", param("\\ABITS"));

manual/CHAPTER_CellLib.tex

@@ -272,6 +272,9 @@ the \B{CLK} input is not used.
 \item \B{CLK\_POLARITY} \\
 Clock is active on positive edge if this parameter has the value {\tt 1'b1} and on the negative
 edge if this parameter is {\tt 1'b0}.
+
+\item \B{PRIORITY} \\
+The cell with the higher integer value in this parameter wins a write conflict.
 \end{itemize}
 
 The HDL frontend models a memory using RTLIL::Memory objects and asynchronous

passes/memory/memory_collect.cc

@@ -20,9 +20,19 @@
 #include "kernel/register.h"
 #include "kernel/log.h"
 #include <sstream>
+#include <algorithm>
 #include <stdlib.h>
 #include <assert.h>
 
+static bool memcells_cmp(RTLIL::Cell *a, RTLIL::Cell *b)
+{
+	if (a->type == "$memrd" && b->type == "$memrd")
+		return a->name < b->name;
+	if (a->type == "$memrd" || b->type == "$memrd")
+		return (a->type == "$memrd") < (b->type == "$memrd");
+	return a->parameters.at("\\PRIORITY").as_int() < b->parameters.at("\\PRIORITY").as_int();
+}
+
 static void handle_memory(RTLIL::Module *module, RTLIL::Memory *memory)
 {
 	log("Collecting $memrd and $memwr for memory `%s' in module `%s':\n",
@@ -48,11 +58,18 @@ static void handle_memory(RTLIL::Module *module, RTLIL::Memory *memory)
 	RTLIL::SigSpec sig_rd_data;
 
 	std::vector<std::string> del_cell_ids;
+	std::vector<RTLIL::Cell*> memcells;
 
-	for (auto &cell_it : module->cells)
-	{
+	for (auto &cell_it : module->cells) {
 		RTLIL::Cell *cell = cell_it.second;
+		if ((cell->type == "$memwr" || cell->type == "$memrd") && cell->parameters["\\MEMID"].decode_string() == memory->name)
+			memcells.push_back(cell);
+	}
 
+	std::sort(memcells.begin(), memcells.end(), memcells_cmp);
+
+	for (auto cell : memcells)
+	{
 		if (cell->type == "$memwr" && cell->parameters["\\MEMID"].decode_string() == memory->name)
 		{
 			wr_ports++;

tests/simple/memory.v

@@ -1,4 +1,21 @@
 
+module test00(clk, setA, setB, y);
+
+input clk, setA, setB;
+output y;
+reg mem [1:0];
+
+always @(posedge clk) begin
+	if (setA) mem[0] <= 0;  // this is line 9
+	if (setB) mem[0] <= 1;  // this is line 10
+end
+
+assign y = mem[0];
+
+endmodule
+
+// ----------------------------------------------------------
+
 module test01(clk, wr_en, wr_addr, wr_value, rd_addr, rd_value);
 
 input clk, wr_en;