Fix error in autospeed. #2810

lib/Slic3r/GCode.pm

@@ -313,7 +313,7 @@ sub _extrude_path {
         $speed ||= $self->volumetric_speed / $path->mm3_per_mm;
     }
     my $F = $speed * 60;  # convert mm/sec to mm/min
-    
+    use XXX; YYY $path->role, $speed, $self->volumetric_speed if $F == 0;
     # extrude arc or line
     $gcode .= ";_BRIDGE_FAN_START\n" if $path->is_bridge && $self->enable_cooling_markers;
     my $path_length = unscale $path->length;