Re: [PATCH] options, lto: Optimize streaming of optimization nodes

[Jakub Jelinek <jakub@redhat.com>]

On Mon, Sep 14, 2020 at 11:02:26AM +0200, Jan Hubicka wrote:
> Especially for the new param machinery, most of streamed values are
> probably going to be the default values.  Perhaps somehow we could
> stream them more effectively.

Ah, that seems like a good idea, that brings further savings, the size
goes down from 574 bytes to 273 bytes, i.e. less than half.
Here is an updated version that does that.  Not trying to handle
enums because the code doesn't know if (enum ...) 10 is even valid,
similarly non-parameters because those really generally don't have large
initializers, and params without Init (those are 0 initialized and thus
don't need to be handled).

2020-09-14  Jakub Jelinek  <jakub@redhat.com>

	* optc-save-gen.awk: Initialize var_opt_init.  In
	cl_optimization_stream_out use bp_pack_var_len_{int,unsigned} instead
	of bp_pack_value and for params with default values larger than 10, xor
	the default value with the actual parameter value.  In
	cl_optimization_stream_in use bp_unpack_var_len_{int,unsigned}
	instead of bp_unpack_value and repeat the above xor.  Formatting fix.

--- gcc/optc-save-gen.awk.jj	2020-09-14 10:51:54.493740942 +0200
+++ gcc/optc-save-gen.awk	2020-09-14 11:39:39.441602594 +0200
@@ -1186,6 +1186,7 @@ for (i = 0; i < n_opts; i++) {
 		var_opt_val_type[n_opt_val] = otype;
 		var_opt_val[n_opt_val] = "x_" name;
 		var_opt_hash[n_opt_val] = flag_set_p("Optimization", flags[i]);
+		var_opt_init[n_opt_val] = opt_args("Init", flags[i]);
 		n_opt_val++;
 	}
 }
@@ -1257,8 +1258,21 @@ for (i = 0; i < n_opt_val; i++) {
 	otype = var_opt_val_type[i];
 	if (otype ~ "^const char \\**$")
 		print "  bp_pack_string (ob, bp, ptr->" name", true);";
-	else
-		print "  bp_pack_value (bp, ptr->" name", 64);";
+	else {
+		if (otype ~ "^unsigned") {
+			sgn = "unsigned";
+		} else {
+			sgn = "int";
+		}
+		if (name ~ "^x_param" && !(otype ~ "^enum ") && var_opt_init[i]) {
+			print "  if (" var_opt_init[i] " > (" var_opt_val_type[i] ") 10)";
+			print "    bp_pack_var_len_" sgn " (bp, ptr->" name" ^ " var_opt_init[i] ");";
+			print "  else";
+			print "    bp_pack_var_len_" sgn " (bp, ptr->" name");";
+		} else {
+			print "  bp_pack_var_len_" sgn " (bp, ptr->" name");";
+		}
+	}
 }
 print "  for (size_t i = 0; i < sizeof (ptr->explicit_mask) / sizeof (ptr->explicit_mask[0]); i++)";
 print "    bp_pack_value (bp, ptr->explicit_mask[i], 64);";
@@ -1274,14 +1288,23 @@ print "{";
 for (i = 0; i < n_opt_val; i++) {
 	name = var_opt_val[i]
 	otype = var_opt_val_type[i];
-	if (otype ~ "^const char \\**$")
-	{
-	      print "  ptr->" name" = bp_unpack_string (data_in, bp);";
-	      print "  if (ptr->" name")";
-	      print "    ptr->" name" = xstrdup (ptr->" name");";
+	if (otype ~ "^const char \\**$") {
+		print "  ptr->" name" = bp_unpack_string (data_in, bp);";
+		print "  if (ptr->" name")";
+		print "    ptr->" name" = xstrdup (ptr->" name");";
+	}
+	else {
+		if (otype ~ "^unsigned") {
+			sgn = "unsigned";
+		} else {
+			sgn = "int";
+		}
+		print "  ptr->" name" = (" var_opt_val_type[i] ") bp_unpack_var_len_" sgn " (bp);";
+		if (name ~ "^x_param" && !(otype ~ "^enum ") && var_opt_init[i]) {
+			print "  if (" var_opt_init[i] " > (" var_opt_val_type[i] ") 10)";
+			print "    ptr->" name" ^= " var_opt_init[i] ";";
+		}
 	}
-	else
-	      print "  ptr->" name" = (" var_opt_val_type[i] ") bp_unpack_value (bp, 64);";
 }
 print "  for (size_t i = 0; i < sizeof (ptr->explicit_mask) / sizeof (ptr->explicit_mask[0]); i++)";
 print "    ptr->explicit_mask[i] = bp_unpack_value (bp, 64);";


	Jakub