https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105769

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |matz at gcc dot gnu.org

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
And just statements that refer to those 3 variables that (incorrectly) share
the stack slot + basic block boundaries.
grep 'bias\|D.5698\|D.5681\|:' /tmp/00
  struct struct void D.5698;
  struct map_t D.5681;
  struct vec bias;
  <bb 2> [local count: 1073741829]:
  _12 = (long unsigned int) &bias;
  bias ={v} {CLOBBER};
  __ct_comp  (&D.5698.__est, &D.5682);
  <bb 3> [local count: 1073741824]:
  MEM <vector(2) long unsigned int> [(void *)&D.5698 + 32B] = _21;
  <bb 4> [local count: 1073741824]:
  __ct_comp  (_14, &D.5698.__est);
  <bb 5> [local count: 1073741824]:
  vect__16.52_79 = MEM <vector(2) long unsigned int> [(void *)&D.5698 + 32B];
  __dt_base  (&MEM[(struct function *)&D.5698].D.5235);
  D.5698 ={v} {CLOBBER};
  D.5698 ={v} {CLOBBER(eol)};
  MEM <char[16]> [(struct _Function_base *)&D.5681] = {};
  MEM <vector(2) long unsigned int> [(bool (*<T72d>) (union _Any_data &
{ref-all}, const union _Any_data & {ref-all}, _Manager_operation) *)&D.5681 +
16B] = _84;
  <bb 6> [count: 0]:
<L5>:
  <bb 7> [count: 0]:
<L4>:
  __dt_base  (&MEM[(struct function *)&D.5698].D.5235);
  D.5698 ={v} {CLOBBER};
  <bb 8> [local count: 429496]:
  <bb 9> [local count: 1073312328]:
  _19 (&D.5683.D.5217._M_functor, &D.5681);
  <bb 10> [local count: 1073312328]:
  __dt_base  (&D.5681.D.5223);
  D.5681 ={v} {CLOBBER};
  D.5681 ={v} {CLOBBER(eol)};
  bias ={v} {CLOBBER(eol)};
  <bb 11> [count: 0]:
<L0>:
  __dt_base  (&D.5681.D.5223);
  D.5681 ={v} {CLOBBER};
  D.5681 ={v} {CLOBBER(eol)};
  <bb 12> [count: 0]:
<L2>:
  D.5698 ={v} {CLOBBER};

Now, perhaps the sharing of stack slot between D.5681 and D.5698 is fine, seems
D.5698 is destructed before D.5681 is constructed:
  D.5698 ={v} {CLOBBER};
  D.5698 ={v} {CLOBBER(eol)};
  MEM <char[16]> [(struct _Function_base *)&D.5681] = {};
and D.5698 is later used just in EH block reachable only from earlier basic
blocks
or just as
  D.5698 ={v} {CLOBBER};
in the last EH bb.  But the sharing of the stack slot in between bias and
D.5698 looks wrong.  What can be seen in the IL is:
  _12 = (long unsigned int) &bias;
which has been hoisted before the
  bias ={v} {CLOBBER};
statement by the slp1 pass.
From:
;;   basic block 2, loop depth 0
;;    pred:       ENTRY
  _3 = operator<< (&cout, "will do (ab)");
  endl (_3);
  MEM[(struct vec *)&cov_jn] ={v} {CLOBBER};
  bias ={v} {CLOBBER};
  MEM[(struct function *)&D.5682] ={v} {CLOBBER};
  MEM <char[16]> [(struct _Function_base *)&D.5682] = {};
  MEM[(struct function *)&D.5682]._M_invoker = _M_invoke;
  MEM[(struct function *)&D.5682].D.5235._M_manager = _M_manager;
  __ct_comp  (&D.5698.__est, &D.5682);
;;    succ:       5
;;                18

;;   basic block 5, loop depth 0
;;    pred:       2
  D.5698.__cov = &cov_jn;
  D.5698.__bias = &bias;
in dse4 to:
;;   basic block 2, loop depth 0
;;    pred:       ENTRY
  _12 = VIEW_CONVERT_EXPR<long unsigned int>(&bias);
  _15 = VIEW_CONVERT_EXPR<long unsigned int>(&cov_jn);
  _21 = {_15, _12};
  _9 = VIEW_CONVERT_EXPR<long unsigned int>(_M_invoke);
  _10 = VIEW_CONVERT_EXPR<long unsigned int>(_M_manager);
  _8 = {_10, _9};
  _3 = operator<< (&cout, "will do (ab)");
  endl (_3);
  MEM[(struct vec *)&cov_jn] ={v} {CLOBBER};
  bias ={v} {CLOBBER};
  MEM[(struct function *)&D.5682] ={v} {CLOBBER};
  MEM <char[16]> [(struct _Function_base *)&D.5682] = {};
  MEM <vector(2) long unsigned int> [(bool (*<T72d>) (union _Any_data &
{ref-all}, const union _Any_data & {ref-all}, _Manager_operation) *)&D.5682 +
16B] = _8;
  __ct_comp  (&D.5698.__est, &D.5682);
;;    succ:       5
;;                18

;;   basic block 5, loop depth 0
;;    pred:       2
  MEM <vector(2) long unsigned int> [(void *)&D.5698 + 32B] = _21;
in slp1.

Is that what is incorrect? And we should never hoist taking of addresses before
a clobber on that var?

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