genemit: Print file+line in the "Splitting with" message

It's tiresome to have to look in insn-emit.c to see where some split
came from, so let's print that info to the dump file as well.  But
don't print the full path, just the basename, for greater readability.


	* genemit.c (gen_split): Print the filename and line number where the
	splitter (or peephole2) was defined, to the dump file.

From-SVN: r275497

gcc/ChangeLog

+2019-09-08  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	* genemit.c (gen_split): Print the filename and line number where the
+	splitter (or peephole2) was defined, to the dump file.
+
 2019-09-07  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/91665

gcc/genemit.c

@@ -609,9 +609,14 @@ gen_split (md_rtx_info *info)
   if (GET_CODE (split) == DEFINE_PEEPHOLE2)
     output_peephole2_scratches (split);
 
+  const char *fn = info->loc.filename;
+  for (const char *p = fn; *p; p++)
+    if (*p == '/')
+      fn = p + 1;
+
   printf ("  if (dump_file)\n");
-  printf ("    fprintf (dump_file, \"Splitting with gen_%s_%d\\n\");\n",
-	  name, info->index);
+  printf ("    fprintf (dump_file, \"Splitting with gen_%s_%d (%s:%d)\\n\");\n",
+	  name, info->index, fn, info->loc.lineno);
 
   printf ("  start_sequence ();\n");