[PATCH] middle-end/97855 - fix diagnostic with default pretty printer

[Richard Biener]

The default diagnostic tree printer relies on dump_generic_node which
for some reason manages to clobber the diagnostic pretty-printer state
so we see garbled diagnostics like

/home/rguenther/src/trunk/gcc/calls.c: In function 'expand_call':
D.6750.coeffs[0]'/home/rguenther/src/trunk/gcc/dojump.c:118:28: warning:  may 
be used uninitialized in this function [-Wmaybe-uninitialized]

when the diagnostic is emitted by the LTO fronted.  The following
approach using a temporary pretty-printer for the dump_generic_node
call fixes this for some unknown reason and we issue

/home/rguenther/src/trunk/gcc/calls.c: In function 'expand_call':
/home/rguenther/src/trunk/gcc/dojump.c:118:28: warning: 'MEM[(struct poly_int 
*)&save].D.6750.coeffs[0]' may be used uninitialized in this function 
[-Wmaybe-uninitialized]

[LTO] Bootstrapped and tested on x86_64-unknown-linux-gnu, OK for trunk?

Thanks,
Richard.

2021-02-26  Richard Biener  <rguent...@suse.de>

        PR middle-end/97855
        * tree-diagnostic.c (default_tree_printer): Use a temporary
        pretty-printer when formatting a tree via dump_generic_node.
---
 gcc/tree-diagnostic.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gcc/tree-diagnostic.c b/gcc/tree-diagnostic.c
index 95b8ef30070..f124e627aad 100644
--- a/gcc/tree-diagnostic.c
+++ b/gcc/tree-diagnostic.c
@@ -300,7 +300,11 @@ default_tree_printer (pretty_printer *pp, text_info *text, 
const char *spec,
       pp_string (pp, n);
     }
   else
-    dump_generic_node (pp, t, 0, TDF_SLIM, 0);
+    {
+      pretty_printer buffer;
+      dump_generic_node (&buffer, t, 0, TDF_SLIM, 0);
+      pp_string (pp, pp_formatted_text (&buffer));
+    }
 
   return true;
 }
-- 
2.26.2