[Bug tree-optimization/56223] Integer ABS is not recognized for more complicated pattern

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56223

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
There are ways of handling this case.  I think the second one is better than
the first.  The first is mentioned here.
The second would take:


if (a) {
  foo();
  b = d + e;
} else {
  goo();
  b = d -e;
}
and replace it with:
if (a) {
  foo();
  t = e;
} else {
  goo();
  t = -e;
}
b = d + t;
And then because in the original case foo and goo were non-existant, PHI-OPT
would replace the if statement with:
t = abs(e);
b = d + t;