[Bug other/70185] fdump-tree-all-graph produces invalid dot files

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70185

--- Comment #1 from vries at gcc dot gnu.org ---
Created attachment 37934
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37934&action=edit
tentative patch

No more warnings, also for rtl:
...
$ rm *.c.* ; gcc test.c -O2 -S -fdump-tree-all-graph -fdump-rtl-all-graph  
$ for f in *.dot; do dot -Tpdf $f -o dot.pdf; done
$ 
...