[Bug tree-optimization/103221] evrp removes |SIGN but does not propagate the ssa name

[amacleod at redhat dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103221

--- Comment #11 from Andrew Macleod <amacleod at redhat dot com> ---
Created attachment 64584
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=64584&action=edit
Patch to add a copy prop pass

EVRP produces:

signed char f (signed char a)
{
  signed char v;

  <bb 2> :
  if (a_2(D) < 0)
    goto <bb 3>; [INV]
  else
    goto <bb 4>; [INV]

  <bb 3> :
  v_4 = a_2(D);

  <bb 4> :
  # v_1 = PHI <a_2(D)(2), v_4(3)>
  return v_1;

}

And adding a copy prop pass right after EVRP produces :

signed char f (signed char a)
{
  signed char v;

  <bb 2> :
  return a_2(D);

}

I think something to that effect is your solution.