[Bug c++/81586] New: valgrind error in output_buffer_append_r with -Wall

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81586

            Bug ID: 81586
           Summary: valgrind error in output_buffer_append_r with -Wall
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

Created attachment 41848
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41848&action=edit
C++ source code

The attached C++ code, when compiled by recent gcc trunk and 
compiler flag -Wall, does this:

==19553== Conditional jump or move depends on uninitialised value(s)
==19553==    at 0x1227643: output_buffer_append_r (pretty-print.h:128)
==19553==    by 0x1227643: pp_append_r (pretty-print.c:258)
==19553==    by 0x1227643: pp_append_text(pretty_printer*, char const*, char
con
st*) (pretty-print.c:892)
==19553==    by 0x12285E9: pp_format(pretty_printer*, text_info*)
(pretty-print.
c:670)

The bug seems to have been created between revisions 243987 and 249539.