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From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug middle-end/102697] [12 Regression] overflow warning missing
 after -O2 vectorization
Date: Thu, 16 Dec 2021 20:00:22 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102697

--- Comment #4 from Martin Sebor <msebor at gcc dot gnu.org> ---
The warning for the test in comment #0 fails to trigger because of the hack
below in pointer-query.cc:

/* A helper of compute_objsize_r() to determine the size from MEM_REF
   MREF.  Return true on success and false on failure.  */

static bool
handle_mem_ref (tree mref, gimple *stmt, int ostype, access_ref *pref,
                ssa_name_limit_t &snlim, pointer_query *qry)
{
  gcc_assert (TREE_CODE (mref) =3D=3D MEM_REF);

  tree mreftype =3D TYPE_MAIN_VARIANT (TREE_TYPE (mref));
  if (VECTOR_TYPE_P (mreftype))
      {
      /* Hack: Handle MEM_REFs of vector types as those to complete
         objects; those may be synthesized from multiple assignments
         to consecutive data members (see PR 93200 and 96963).
         FIXME: Vectorized assignments should only be present after
         vectorization so this hack is only necessary after it has
         run and could be avoided in calls from prior passes (e.g.,
         tree-ssa-strlen.c).
         FIXME: Deal with this more generally, e.g., by marking up
         such MEM_REFs at the time they're created.  */
      ostype =3D 0;
    }=