[Bug tree-optimization/91996] fold non-constant strlen relational expressions

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91996

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
           Keywords|                            |missed-optimization
   Last reconfirmed|                            |2019-10-04
           Assignee|unassigned at gcc dot gnu.org      |msebor at gcc dot 
gnu.org
             Blocks|                            |83819
     Ever confirmed|0                           |1
   Target Milestone|---                         |10.0
           Severity|normal                      |enhancement

--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
This enhancement is what the FIXME in tree-ssa-strlen.c refers to:

static bool
count_nonzero_bytes (tree exp, unsigned HOST_WIDE_INT offset,
                     unsigned HOST_WIDE_INT nbytes,
                     unsigned lenrange[3], bool *nulterm,
                     bool *allnul, bool *allnonnul, ssa_name_limit_t &snlim)
{
  int idx = get_stridx (exp);
  if (idx > 0)
    {
      strinfo *si = get_strinfo (idx);
      /* FIXME: Handle non-constant lengths in some range.  */
      if (!si || !tree_fits_shwi_p (si->nonzero_chars))
        return false;


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83819
[Bug 83819] [meta-bug] missing strlen optimizations