[Bug middle-end/104986] [12 Regression] bogus writing 1 byte into a region of size 0 with -fwrapv and -O2 -fpeel-loops since r12-4698-gf6d012338bf87f42

[amacleod at redhat dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104986

--- Comment #7 from Andrew Macleod <amacleod at redhat dot com> ---
and I forgot to show to dom3 output which did the transformation:

j.c.195t.dom3:Match-and-simplified (sizetype) nb_66 to 18446744073709551615
j.c.195t.dom3:Optimizing statement _2 = (sizetype) nb_66;
j.c.195t.dom3:  Replaced 'nb_66' with constant '-1'
j.c.195t.dom3:  nb_66 = -1;

but for whatever reason it could not reduce nb_58 to anything better than [-1,
0]

nb_58 = prephitmp_30 + -5;
Intersecting
  int [-1, 0]
and
  int [-1, 4]
to
  int [-1, 0]