[Bug tree-optimization/114999] A few missing optimizations due to `a - b` and `b - a` not being detected as negatives of each other

[jschmitz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114999

--- Comment #12 from Jennifer Schmitz <jschmitz at gcc dot gnu.org> ---
Created attachment 60149
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=60149&action=edit
Proposed patch for detecting abs diff for signed integers