From 367cdf5708659bf10c934185f2efa3f10304b548 Mon Sep 17 00:00:00 2001
From: Brian Taylor <lbwnet@comcast.net>
Date: Fri, 29 Mar 2024 18:26:01 -0700
Subject: [PATCH] Add variable ps_scan_gates_optimize (default 1). If < 1, then
 turn off the optimizations in scan_gates.

---
 src/frontend/logicexp.c        | 23 ++++++++++-------------
 src/frontend/udevices.c        |  6 +++++-
 src/include/ngspice/logicexp.h |  2 +-
 3 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/src/frontend/logicexp.c b/src/frontend/logicexp.c
index 8d2ccad37..62befc434 100644
--- a/src/frontend/logicexp.c
+++ b/src/frontend/logicexp.c
@@ -570,16 +570,12 @@ static void move_inputs(struct gate_data *curr, struct gate_data *prev)
     prev->finished = TRUE;
 }
 
-static void scan_gates(DSTRING *lhs)
+static void scan_gates(DSTRING *lhs, int optimize)
 {
     struct gate_data *current = NULL, *previous = NULL, *last_curr = NULL;
     struct gate_data *prev = NULL;
-    int ps_scan_gates_noopt = 0;
 
-    if (!cp_getvar("ps_scan_gates_noopt", CP_NUM, &ps_scan_gates_noopt, 0)) {
-        ps_scan_gates_noopt = 0;
-    }
-    if (ps_scan_gates_noopt) {
+    if (optimize < 1) {
         current = last_gate;
         if (ds_get_length(lhs) > 0) {
             assert(current->finished == FALSE);
@@ -982,7 +978,7 @@ err_return:
 /* Start of logicexp parser */
 static void aerror(char *s);
 static BOOL amatch(int t);
-static BOOL bparse(char *line, BOOL new_lexer);
+static BOOL bparse(char *line, BOOL new_lexer, int optimize);
 
 static int lookahead = 0;
 static int number_of_instances = 0;
@@ -1077,7 +1073,7 @@ static BOOL amatch(int t)
     return TRUE;
 }
 
-static BOOL bstmt_postfix(void)
+static BOOL bstmt_postfix(int optimize)
 {
     /* A stmt is: output_name_id = '{' expr '}' */
     DS_CREATE(lhs, 32);
@@ -1129,7 +1125,7 @@ static BOOL bstmt_postfix(void)
         retval = FALSE;
         goto bail_out;
     }
-    scan_gates(&lhs);
+    scan_gates(&lhs, optimize);
     gen_scanned_gates(first_gate);
     lookahead = lex_scan();
     while (lookahead != '}') {
@@ -1172,7 +1168,7 @@ static char *get_logicexp_tmodel_delays(
     return ds_get_buf(mname);
 }
 
-static BOOL bparse(char *line, BOOL new_lexer)
+static BOOL bparse(char *line, BOOL new_lexer, int optimize)
 {
     BOOL ret_val = TRUE;
     DS_CREATE(stmt, LEX_BUF_SZ);
@@ -1187,7 +1183,7 @@ static BOOL bparse(char *line, BOOL new_lexer)
     while (lookahead != '\0') {
         ds_clear(&stmt);
         ds_cat_str(&stmt, parse_lexer->lexer_buf);
-        if (!bstmt_postfix()) {
+        if (!bstmt_postfix(optimize)) {
             cleanup_parser();
             ret_val= FALSE;
             break;
@@ -1249,8 +1245,9 @@ static BOOL expect_token(
     return TRUE;
 }
 
-BOOL f_logicexp(char *line)
+BOOL f_logicexp(char *line, int optimize)
 {
+    /* If optimize > 0 then perform optimizations in scan_gates */
     int t, num_ins = 0, num_outs = 0, i;
     char *endp;
     BOOL ret_val = TRUE;
@@ -1335,7 +1332,7 @@ BOOL f_logicexp(char *line)
     }
     (void) add_sym_tab_entry(parse_lexer->lexer_buf,
         SYM_TMODEL, &parse_lexer->lexer_sym_tab);
-    ret_val = bparse(line, FALSE);
+    ret_val = bparse(line, FALSE, optimize);
 
     current_lexer = NULL;
     if (!ret_val) {
diff --git a/src/frontend/udevices.c b/src/frontend/udevices.c
index dcbe5d054..b7437f45e 100644
--- a/src/frontend/udevices.c
+++ b/src/frontend/udevices.c
@@ -280,6 +280,7 @@ static int ps_udevice_msgs = 0;  // Controls the verbosity of U* warnings
   If ps_udevice_exit is non-zero then exit when u_process_instance fails
 */
 static int ps_udevice_exit = 0;
+static int ps_scan_gates_optimize = 1;  // Allow optimization in scan_gates
 static int ps_tpz_delays = 0;  // For tristate delays
 static int ps_with_inverters = 0;  // For ff/latch control inputs
 static int ps_with_tri_inverters = 0;  // For inv3/inv3a data inputs
@@ -965,6 +966,9 @@ void initialize_udevice(char *subckt_line)
     if (!cp_getvar("ps_udevice_exit", CP_NUM, &ps_udevice_exit, 0)) {
         ps_udevice_exit = 0;
     }
+    if (!cp_getvar("ps_scan_gates_optimize", CP_NUM, &ps_scan_gates_optimize, 0)) {
+        ps_scan_gates_optimize = 1;
+    }
     /* If non-zero use inverters with ff/latch control inputs */
     if (!cp_getvar("ps_with_inverters", CP_NUM, &ps_with_inverters, 0)) {
         ps_with_inverters = 0;
@@ -4318,7 +4322,7 @@ BOOL u_process_instance(char *nline)
             if (ps_ports_and_pins & 4) {
                 printf("TRANS_IN  %s\n", nline);
             }
-            behav_ret = f_logicexp(nline);
+            behav_ret = f_logicexp(nline, ps_scan_gates_optimize);
             if (!behav_ret && current_subckt) {
                 fprintf(stderr, "ERROR in %s\n", current_subckt);
             }
diff --git a/src/include/ngspice/logicexp.h b/src/include/ngspice/logicexp.h
index 556835a43..8c77e9a09 100644
--- a/src/include/ngspice/logicexp.h
+++ b/src/include/ngspice/logicexp.h
@@ -3,7 +3,7 @@
 #ifndef INCLUDED_LOGICEXP_H
 #define INCLUDED_LOGICEXP_H
 
-BOOL f_logicexp(char *line);
+BOOL f_logicexp(char *line, int optimize);
 BOOL f_pindly(char *line);
 
 #endif