Re: [PATCH] Fix PR81354 (rewrite gimple_split_edge)

[Bill Schmidt <wschmidt at linux dot vnet dot ibm dot com>]

On Aug 2, 2017, at 3:09 AM, Richard Biener <richard.guenther@gmail.com> wrote:
> 
> On Tue, Aug 1, 2017 at 5:56 PM, Bill Schmidt
> <wschmidt@linux.vnet.ibm.com> wrote:
>> On Aug 1, 2017, at 8:50 AM, Bill Schmidt <wschmidt@linux.vnet.ibm.com> wrote:
>>> 
>>> On Aug 1, 2017, at 7:44 AM, Bill Schmidt <wschmidt@linux.vnet.ibm.com> wrote:
>>>> 
>>>>> 
>>>>> On Aug 1, 2017, at 3:46 AM, Richard Biener <richard.guenther@gmail.com> wrote:
>>>>> 
>>>>> On Mon, Jul 31, 2017 at 4:03 PM, Bill Schmidt
>>>>> <wschmidt@linux.vnet.ibm.com> wrote:
>>>>>> 
>>>>>>> On Jul 31, 2017, at 8:19 AM, Bill Schmidt <wschmidt@linux.vnet.ibm.com> wrote:
>>>>>>> 
>>>>>>> That would certainly be much simpler!  I'll regstrap it and test it on the other
>>>>>>> occurrence I've found to be certain.
>>>>>> 
>>>>>> Unfortunately, this fails bootstrap:
>>>>>> 
>>>>>> /home/wschmidt/gcc/gcc-mainline-test/gcc/calls.c: In function 'rtx_def* emit_library_call_value_1(int, rtx, rtx, libcall_type, machine_mode, int, va_list)':
>>>>>> /home/wschmidt/gcc/gcc-mainline-test/gcc/calls.c:4362:1: error: definition in block 214 does not dominate use in block 14
>>>>>> emit_library_call_value_1 (int retval, rtx orgfun, rtx value,
>>>>>> ^~~~~~~~~~~~~~~~~~~~~~~~~
>>>>>> for SSA_NAME: slsr_772 in statement:
>>>>>> slsr_749 = PHI <_17(26), slsr_772(14), slsr_334(214)>
>>>>>> PHI argument
>>>>>> slsr_772
>>>>>> for PHI node
>>>>>> slsr_749 = PHI <_17(26), slsr_772(14), slsr_334(214)>
>>>>>> during GIMPLE pass: slsr
>>>>>> /home/wschmidt/gcc/gcc-mainline-test/gcc/calls.c:4362:1: internal compiler error: verify_ssa failed
>>>>>> 0x11567cf3 verify_ssa(bool, bool)
>>>>>>     /home/wschmidt/gcc/gcc-mainline-test/gcc/tree-ssa.c:1186
>>>>>> 0x10fc3fff execute_function_todo
>>>>>>     /home/wschmidt/gcc/gcc-mainline-test/gcc/passes.c:1997
>>>>>> 0x10fc277f do_per_function
>>>>>>     /home/wschmidt/gcc/gcc-mainline-test/gcc/passes.c:1655
>>>>>> 0x10fc42a3 execute_todo
>>>>>>     /home/wschmidt/gcc/gcc-mainline-test/gcc/passes.c:2044
>>>>>> Please submit a full bug report,
>>>>>> with preprocessed source if appropriate.
>>>>>> Please include the complete backtrace with any bug report.
>>>>>> See <https://gcc.gnu.org/bugs/> for instructions.
>>>>>> 
>>>>>> Not terribly surprising given how sensitive this stuff is.  I can look into why
>>>>>> this fails, but looks like it can't be quite this simple, sadly.
>>>>> 
>>>>> Intersting ... a dg-torture.exp run was clean for me (all I
>>>>> tested...).  So yes, can you
>>>>> check what fails?  Maybe run the testsuite with the stage1 compiler.
>>>> 
>>>> Looks like it's the stage1 that doesn't build.  I think the difference is
>>>> that I was building trunk and you were building 6.  I'll try to look into
>>>> it later today after I get through some meetings.
>>> 
>>> Sorry, no, it was stage 2 where the failure occurs.
>> 
>> Ah, "good" news.  I believe the bootstrap failure with this change is another
>> rediscovery of https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81503, which
>> explains why it wasn't seen for GCC 6.  I'll work on getting that fixed and
>> then try this again.
> 
> Note I very much would like to "fix" split_edge on trunk, on release branches
> I'd appreciate if a simpler fix inside SLSR works, like using gsi_insert_on_edge
> to avoid splitting edges during the iteration.

Sure, I'll look into it.

Bill
> 
> Richard.
> 
>> Bill
>> 
>>> 
>>> Bill
>>> 
>>>> 
>>>> Bill
>>>>> 
>>>>> Richard.
>>>>> 
>>>>>> Bill
>>>>>> 
>>>>>>> 
>>>>>>> -- Bill
>>>>>>> 
>>>>>>>> On Jul 31, 2017, at 4:15 AM, Richard Biener <richard.guenther@gmail.com> wrote:
>>>>>>>> 
>>>>>>>> On Sun, Jul 30, 2017 at 8:04 PM, Bill Schmidt
>>>>>>>> <wschmidt@linux.vnet.ibm.com> wrote:
>>>>>>>>> Hi,
>>>>>>>>> 
>>>>>>>>> PR81354 identifies a latent bug that can happen in SLSR since the
>>>>>>>>> conditional candidate support was first added.  SLSR relies on the
>>>>>>>>> address of a GIMPLE PHI remaining constant during the course of the
>>>>>>>>> optimization pass, but it needs to split edges.  The use of
>>>>>>>>> make_single_succ_edge and reinstall_phi_args in gimple_split_edge
>>>>>>>>> causes GIMPLE PHI statements to be temporarily expanded to add a
>>>>>>>>> predecessor, and then rebuilt to have the original number of
>>>>>>>>> predecessors.  The expansion usually, if not always, causes the PHI
>>>>>>>>> statement to change address.  Thus gimple_split_edge needs to be
>>>>>>>>> rewritten to perform in-situ replacement of PHI arguments.
>>>>>>>>> 
>>>>>>>>> The required pieces of make_single_succ_edge have been extracted into
>>>>>>>>> two places:  make_replacement_pred_edge, and some fixup code at the
>>>>>>>>> end of gimple_split_edge.  The division is necessary because the
>>>>>>>>> destination of the original edge must remember its original
>>>>>>>>> predecessors for the switch processing in
>>>>>>>>> gimple_redirect_edge_and_branch_1 to work properly.
>>>>>>>>> 
>>>>>>>>> The function gimple_redirect_edge_and_branch was factored into two
>>>>>>>>> pieces so that most of it can be used by gimple_split_edge without
>>>>>>>>> calling ssa_redirect_edge, which also interferes with PHIs.  The
>>>>>>>>> useful bits of ssa_redirect_edge are factored out into the next three
>>>>>>>>> lines of gimple_split_edge.
>>>>>>>>> 
>>>>>>>>> Similarly, redirect_eh_edge had already been similarly factored into
>>>>>>>>> redirect_eh_edge_1 and ssa_redirect_edge.  I took advantage of that
>>>>>>>>> and exposed redirect_eh_edge_1 for use in gimple_redirect_edge_and_branch_1.
>>>>>>>>> 
>>>>>>>>> I've added the test from PR81354 as a torture test, but as we've seen,
>>>>>>>>> small changes elsewhere in the optimizer can easily hide the problem.
>>>>>>>>> 
>>>>>>>>> Bootstrapped and tested on powerpc64le-linux-gnu with no regressions.
>>>>>>>>> Is this ok for trunk?  Eventually this needs to be backported to GCC 5,
>>>>>>>>> 6, and 7 if that's acceptable, since PR81354 was observed on
>>>>>>>>> gcc-5-branch.  I haven't yet prepared the backports.
>>>>>>>> 
>>>>>>>> I don't like make_replacement_pred_edge too much.  Wouldn't it work
>>>>>>>> to make sure we first shrink and then re-grow like if we simply do the
>>>>>>>> redirect_edge_and_branch before the make_single_succ_edge call?
>>>>>>>> At least quick testing shows it fixes the testcase on the GCC 6 branch for me.
>>>>>>>> 
>>>>>>>> Index: gcc/tree-cfg.c
>>>>>>>> ===================================================================
>>>>>>>> --- gcc/tree-cfg.c      (revision 250732)
>>>>>>>> +++ gcc/tree-cfg.c      (working copy)
>>>>>>>> @@ -2753,12 +2753,16 @@ gimple_split_edge (edge edge_in)
>>>>>>>> new_bb = create_empty_bb (after_bb);
>>>>>>>> new_bb->frequency = EDGE_FREQUENCY (edge_in);
>>>>>>>> new_bb->count = edge_in->count;
>>>>>>>> +
>>>>>>>> +  /* First redirect the existing edge to avoid reallocating
>>>>>>>> +     PHI nodes in dest.  */
>>>>>>>> +  e = redirect_edge_and_branch (edge_in, new_bb);
>>>>>>>> +  gcc_assert (e == edge_in);
>>>>>>>> +
>>>>>>>> new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
>>>>>>>> new_edge->probability = REG_BR_PROB_BASE;
>>>>>>>> new_edge->count = edge_in->count;
>>>>>>>> 
>>>>>>>> -  e = redirect_edge_and_branch (edge_in, new_bb);
>>>>>>>> -  gcc_assert (e == edge_in);
>>>>>>>> reinstall_phi_args (new_edge, e);
>>>>>>>> 
>>>>>>>> return new_bb;
>>>>>>>> 
>>>>>>>> Sorry for misleading you to a complex solution.
>>>>>>>> 
>>>>>>>> Thanks,
>>>>>>>> Richard.
>>>>>>>> 
>>>>>>>>> Thanks,
>>>>>>>>> Bill
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> [gcc]
>>>>>>>>> 
>>>>>>>>> 2017-07-30  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
>>>>>>>>> 
>>>>>>>>>   PR tree-optimization/81354
>>>>>>>>>   * tree-cfg.c (gimple_redirect_edge_and_branch_1): New decl.
>>>>>>>>>   (reinstall_phi_args): Delete function.
>>>>>>>>>   (make_replacement_pred_edge): New function.
>>>>>>>>>   (gimple_split_edge): Rewrite.
>>>>>>>>>   (gimple_redirect_edge_and_branch_1): New function, factored
>>>>>>>>>   from...
>>>>>>>>>   (gimple_redirect_edge_and_branch): ...here.
>>>>>>>>>   (split_critical_edges): Don't re-split already split edges.
>>>>>>>>>   * tree-eh.c (redirect_eh_edge_1): Make visible.
>>>>>>>>>   * tree-eh.h (redirect_eh_edge_1): Likewise.
>>>>>>>>> 
>>>>>>>>> [gcc/testsuite]
>>>>>>>>> 
>>>>>>>>> 2017-07-30  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
>>>>>>>>> 
>>>>>>>>>   PR tree-optimization/81354
>>>>>>>>>   * g++.dg/torture/pr81354.C: New file.
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> Index: gcc/testsuite/g++.dg/torture/pr81354.C
>>>>>>>>> ===================================================================
>>>>>>>>> --- gcc/testsuite/g++.dg/torture/pr81354.C      (nonexistent)
>>>>>>>>> +++ gcc/testsuite/g++.dg/torture/pr81354.C      (working copy)
>>>>>>>>> @@ -0,0 +1,24 @@
>>>>>>>>> +// PR81354 reported this test as crashing in a limited range of revisions.
>>>>>>>>> +// { dg-do compile }
>>>>>>>>> +
>>>>>>>>> +struct T { double a; double b; };
>>>>>>>>> +
>>>>>>>>> +void foo(T Ad[], int As[2])
>>>>>>>>> +{
>>>>>>>>> +  int j;
>>>>>>>>> +  int i;
>>>>>>>>> +  int Bs[2] = {0,0};
>>>>>>>>> +  T Bd[16];
>>>>>>>>> +
>>>>>>>>> +  for (j = 0; j < 4; j++) {
>>>>>>>>> +    for (i = 0; i + 1 <= j + 1; i++) {
>>>>>>>>> +      Ad[i + As[0] * j] = Bd[i + Bs[0] * j];
>>>>>>>>> +    }
>>>>>>>>> +
>>>>>>>>> +    i = j + 1;  // <- comment out this line and it does not crash
>>>>>>>>> +    for (; i + 1 < 5; i++) {
>>>>>>>>> +      Ad[i + As[0] * j].a = 0.0;
>>>>>>>>> +      Ad[i + As[0] * j].b = 0.0;
>>>>>>>>> +    }
>>>>>>>>> +  }
>>>>>>>>> +}
>>>>>>>>> Index: gcc/tree-cfg.c
>>>>>>>>> ===================================================================
>>>>>>>>> --- gcc/tree-cfg.c      (revision 250721)
>>>>>>>>> +++ gcc/tree-cfg.c      (working copy)
>>>>>>>>> @@ -154,6 +154,7 @@ static void make_gimple_switch_edges (gswitch *, b
>>>>>>>>> static bool make_goto_expr_edges (basic_block);
>>>>>>>>> static void make_gimple_asm_edges (basic_block);
>>>>>>>>> static edge gimple_redirect_edge_and_branch (edge, basic_block);
>>>>>>>>> +static edge gimple_redirect_edge_and_branch_1 (edge, basic_block);
>>>>>>>>> static edge gimple_try_redirect_by_replacing_jump (edge, basic_block);
>>>>>>>>> 
>>>>>>>>> /* Various helpers.  */
>>>>>>>>> @@ -2776,35 +2777,6 @@ last_and_only_stmt (basic_block bb)
>>>>>>>>> return NULL;
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> -/* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE.  */
>>>>>>>>> -
>>>>>>>>> -static void
>>>>>>>>> -reinstall_phi_args (edge new_edge, edge old_edge)
>>>>>>>>> -{
>>>>>>>>> -  edge_var_map *vm;
>>>>>>>>> -  int i;
>>>>>>>>> -  gphi_iterator phis;
>>>>>>>>> -
>>>>>>>>> -  vec<edge_var_map> *v = redirect_edge_var_map_vector (old_edge);
>>>>>>>>> -  if (!v)
>>>>>>>>> -    return;
>>>>>>>>> -
>>>>>>>>> -  for (i = 0, phis = gsi_start_phis (new_edge->dest);
>>>>>>>>> -       v->iterate (i, &vm) && !gsi_end_p (phis);
>>>>>>>>> -       i++, gsi_next (&phis))
>>>>>>>>> -    {
>>>>>>>>> -      gphi *phi = phis.phi ();
>>>>>>>>> -      tree result = redirect_edge_var_map_result (vm);
>>>>>>>>> -      tree arg = redirect_edge_var_map_def (vm);
>>>>>>>>> -
>>>>>>>>> -      gcc_assert (result == gimple_phi_result (phi));
>>>>>>>>> -
>>>>>>>>> -      add_phi_arg (phi, arg, new_edge, redirect_edge_var_map_location (vm));
>>>>>>>>> -    }
>>>>>>>>> -
>>>>>>>>> -  redirect_edge_var_map_clear (old_edge);
>>>>>>>>> -}
>>>>>>>>> -
>>>>>>>>> /* Returns the basic block after which the new basic block created
>>>>>>>>> by splitting edge EDGE_IN should be placed.  Tries to keep the new block
>>>>>>>>> near its "logical" location.  This is of most help to humans looking
>>>>>>>>> @@ -2825,6 +2797,24 @@ split_edge_bb_loc (edge edge_in)
>>>>>>>>> return dest_prev;
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> +/* Create a single-predecessor edge from SRC to DST, replacing the
>>>>>>>>> +   predecessor edge E_IN of DST, with flags FLAGS.  This is done in
>>>>>>>>> +   situ so that phis in DST will not get re-allocated.  */
>>>>>>>>> +
>>>>>>>>> +static edge
>>>>>>>>> +make_replacement_pred_edge (basic_block src, basic_block dest,
>>>>>>>>> +                           edge e_in, int flags)
>>>>>>>>> +{
>>>>>>>>> +  edge e = ggc_cleared_alloc<edge_def> ();
>>>>>>>>> +  n_edges_for_fn (cfun)++;
>>>>>>>>> +  e->src = src;
>>>>>>>>> +  e->dest = dest;
>>>>>>>>> +  e->flags = flags;
>>>>>>>>> +  vec_safe_push (src->succs, e);
>>>>>>>>> +  e->dest_idx = e_in->dest_idx;
>>>>>>>>> +  return e;
>>>>>>>>> +}
>>>>>>>>> +
>>>>>>>>> /* Split a (typically critical) edge EDGE_IN.  Return the new block.
>>>>>>>>> Abort on abnormal edges.  */
>>>>>>>>> 
>>>>>>>>> @@ -2832,7 +2822,7 @@ static basic_block
>>>>>>>>> gimple_split_edge (edge edge_in)
>>>>>>>>> {
>>>>>>>>> basic_block new_bb, after_bb, dest;
>>>>>>>>> -  edge new_edge, e;
>>>>>>>>> +  edge e, f;
>>>>>>>>> 
>>>>>>>>> /* Abnormal edges cannot be split.  */
>>>>>>>>> gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
>>>>>>>>> @@ -2841,15 +2831,33 @@ gimple_split_edge (edge edge_in)
>>>>>>>>> 
>>>>>>>>> after_bb = split_edge_bb_loc (edge_in);
>>>>>>>>> 
>>>>>>>>> +  /* Create a new block, and an edge F from that block to the original
>>>>>>>>> +     destination.  */
>>>>>>>>> new_bb = create_empty_bb (after_bb);
>>>>>>>>> new_bb->frequency = EDGE_FREQUENCY (edge_in);
>>>>>>>>> new_bb->count = edge_in->count;
>>>>>>>>> -  new_edge = make_single_succ_edge (new_bb, dest, EDGE_FALLTHRU);
>>>>>>>>> +  f = make_replacement_pred_edge (new_bb, dest, edge_in, EDGE_FALLTHRU);
>>>>>>>>> 
>>>>>>>>> -  e = redirect_edge_and_branch (edge_in, new_bb);
>>>>>>>>> +  /* Redirect the original edge to its new successor.  */
>>>>>>>>> +  e = gimple_redirect_edge_and_branch_1 (edge_in, new_bb);
>>>>>>>>> gcc_assert (e == edge_in);
>>>>>>>>> -  reinstall_phi_args (new_edge, e);
>>>>>>>>> +  e->dest = new_bb;
>>>>>>>>> +  vec_safe_push (new_bb->preds, e);
>>>>>>>>> +  e->dest_idx = 0;
>>>>>>>>> 
>>>>>>>>> +  /* Fix up the predecessor edge for DEST to now be F.  We can't do
>>>>>>>>> +     this prior to gimple_redirect_edge_and_branch_1 without raising
>>>>>>>>> +     havoc in the switch code.  */
>>>>>>>>> +  int idx = -1;
>>>>>>>>> +  for (unsigned int i = 0; i < EDGE_COUNT (dest->preds); i++)
>>>>>>>>> +    if (EDGE_PRED (dest, i) == edge_in)
>>>>>>>>> +      {
>>>>>>>>> +       idx = i;
>>>>>>>>> +       break;
>>>>>>>>> +      }
>>>>>>>>> +  gcc_assert (idx != -1);
>>>>>>>>> +  EDGE_PRED (dest, idx) = f;
>>>>>>>>> +
>>>>>>>>> return new_bb;
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> @@ -5740,12 +5748,10 @@ gimple_try_redirect_by_replacing_jump (edge e, bas
>>>>>>>>> return NULL;
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> +/* Primary worker for gimple_redirect_edge_and_branch.  */
>>>>>>>>> 
>>>>>>>>> -/* Redirect E to DEST.  Return NULL on failure.  Otherwise, return the
>>>>>>>>> -   edge representing the redirected branch.  */
>>>>>>>>> -
>>>>>>>>> static edge
>>>>>>>>> -gimple_redirect_edge_and_branch (edge e, basic_block dest)
>>>>>>>>> +gimple_redirect_edge_and_branch_1 (edge e, basic_block dest)
>>>>>>>>> {
>>>>>>>>> basic_block bb = e->src;
>>>>>>>>> gimple_stmt_iterator gsi;
>>>>>>>>> @@ -5759,7 +5765,10 @@ static edge
>>>>>>>>> return NULL;
>>>>>>>>> 
>>>>>>>>> if (e->flags & EDGE_EH)
>>>>>>>>> -    return redirect_eh_edge (e, dest);
>>>>>>>>> +    {
>>>>>>>>> +      redirect_eh_edge_1 (e, dest, false);
>>>>>>>>> +      return e;
>>>>>>>>> +    }
>>>>>>>>> 
>>>>>>>>> if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun))
>>>>>>>>> {
>>>>>>>>> @@ -5887,9 +5896,19 @@ static edge
>>>>>>>>>  gcc_assert (e->flags & EDGE_FALLTHRU);
>>>>>>>>>  break;
>>>>>>>>> }
>>>>>>>>> +  return e;
>>>>>>>>> +}
>>>>>>>>> 
>>>>>>>>> -  /* Update/insert PHI nodes as necessary.  */
>>>>>>>>> +/* Redirect E to DEST.  Return NULL on failure.  Otherwise, return the
>>>>>>>>> +   edge representing the redirected branch.  */
>>>>>>>>> 
>>>>>>>>> +static edge
>>>>>>>>> +gimple_redirect_edge_and_branch (edge e, basic_block dest)
>>>>>>>>> +{
>>>>>>>>> +  edge f = gimple_redirect_edge_and_branch_1 (e, dest);
>>>>>>>>> +  if (f != e)
>>>>>>>>> +    return f;
>>>>>>>>> +
>>>>>>>>> /* Now update the edges in the CFG.  */
>>>>>>>>> e = ssa_redirect_edge (e, dest);
>>>>>>>>> 
>>>>>>>>> @@ -8636,13 +8655,18 @@ split_critical_edges (void)
>>>>>>>>> basic_block bb;
>>>>>>>>> edge e;
>>>>>>>>> edge_iterator ei;
>>>>>>>>> +  int first_free_block;
>>>>>>>>> 
>>>>>>>>> /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
>>>>>>>>> expensive.  So we want to enable recording of edge to CASE_LABEL_EXPR
>>>>>>>>> mappings around the calls to split_edge.  */
>>>>>>>>> start_recording_case_labels ();
>>>>>>>>> +  first_free_block = last_basic_block_for_fn (cfun);
>>>>>>>>> FOR_ALL_BB_FN (bb, cfun)
>>>>>>>>> {
>>>>>>>>> +      /* Don't re-split edges we've already split.  */
>>>>>>>>> +      if (bb->index >= first_free_block)
>>>>>>>>> +       continue;
>>>>>>>>>  FOR_EACH_EDGE (e, ei, bb->succs)
>>>>>>>>>    {
>>>>>>>>>     if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
>>>>>>>>> Index: gcc/tree-eh.c
>>>>>>>>> ===================================================================
>>>>>>>>> --- gcc/tree-eh.c       (revision 250721)
>>>>>>>>> +++ gcc/tree-eh.c       (working copy)
>>>>>>>>> @@ -2279,7 +2279,7 @@ make_eh_edges (gimple *stmt)
>>>>>>>>> If false, we're being called from generic cfg manipulation code and we
>>>>>>>>> should preserve our place within the region tree.  */
>>>>>>>>> 
>>>>>>>>> -static void
>>>>>>>>> +void
>>>>>>>>> redirect_eh_edge_1 (edge edge_in, basic_block new_bb, bool change_region)
>>>>>>>>> {
>>>>>>>>> eh_landing_pad old_lp, new_lp;
>>>>>>>>> Index: gcc/tree-eh.h
>>>>>>>>> ===================================================================
>>>>>>>>> --- gcc/tree-eh.h       (revision 250721)
>>>>>>>>> +++ gcc/tree-eh.h       (working copy)
>>>>>>>>> @@ -32,6 +32,7 @@ extern int lookup_stmt_eh_lp (gimple *);
>>>>>>>>> extern bool make_eh_dispatch_edges (geh_dispatch *);
>>>>>>>>> extern void make_eh_edges (gimple *);
>>>>>>>>> extern edge redirect_eh_edge (edge, basic_block);
>>>>>>>>> +extern void redirect_eh_edge_1 (edge, basic_block, bool);
>>>>>>>>> extern void redirect_eh_dispatch_edge (geh_dispatch *, edge, basic_block);
>>>>>>>>> extern bool operation_could_trap_helper_p (enum tree_code, bool, bool, bool,
>>>>>>>>>                                      bool, tree, bool *);