[ was: Re: [PR65637][PATCH][3/3] Handle 2 preds for fin_bb in 
expand_omp_for_static_chunk ]

On 15/04/15 15:23, Tom de Vries wrote:
> On 15-04-15 15:10, Tom de Vries wrote:
>> Hi,
>>
>> This patch series fixes PR65637.
>>

<SNIP>

> This patch fixes compilation of autopar/reduc-3.c in
> expand_omp_for_static_chunk.
>
> We encounter two situations in expand_omp_for_static_chunk:
> 1. single_pred_p (fin_bb)
>     This situation happens for f.i. autopar-1.c, which uses a compile-time
>     constant loop bound.
> 2. !single_pred_p (fin_bb)
>     This situation happens for autopar/reduc-3.c, which uses a compile-time
>     unknown loop bound.
>
> The two situations are represented as control flow graphs here:
> ...
> 1.
>    x
>    |
>    |
>    *
> entry_bb
>    |
>    |
>    *
> iter_part_bb --* seq_start_bb
>    |        *         |
>    |         \       ...
>    *          \       |
> fin_bb        \      *
>    |            -- trip_update_bb
>    |
>    *
>    x
>
> 2.
>    x
>    |
>    |
>    *
> region.entry --* entry_bb
>    |                |
>    |                |
>    *                *
> fin_bb   *--   iter_part_bb --* seq_start_bb
>    |                       *        |
>    |                        \      ...
>    *                         \      |
>    x                          \     *
>                    -- trip_update_bb
> ...
>
> This patch handles the !single_pred_p (fin_bb) scenario, while keeping the
> single_pred_p (fin_bb) scenario undisturbed.
>
> With the patch, the resulting split-off function looks like this:
> ...
> main1._loopfn.0 (voidD.41 * .paral_data_paramD.2498)
> {
> ;;   basic block 2, loop depth 0, count 0, freq 79, maybe hot
> ;;    prev block 0, next block 3, flags: (NEW, REACHABLE)
> ;;    pred:       ENTRY (FALLTHRU)
>    .paral_data_param_2 = .paral_data_param_1(D);
>    .paral_data_load.12_3 = (struct  *) .paral_data_param_2;
>    # VUSE <.MEM_33(D)>
>    _4 = .paral_data_load.12_3->D.2490;
>    # VUSE <.MEM_33(D)>
>    ub_5 = .paral_data_load.12_3->ubD.2491;
>    # VUSE <.MEM_33(D)>
>    uc_6 = .paral_data_load.12_3->ucD.2492;
>    if (0 < _4)
>      goto <bb 4>;
>    else
>      goto <bb 3>;
> ;;    succ:       4 [100.0%]  (TRUE_VALUE)
> ;;                3 [0.0%]  (FALSE_VALUE)
>
> ;;   basic block 3, loop depth 0, count 0, freq 0, maybe hot
> ;;    prev block 2, next block 4, flags: (NEW, REACHABLE)
> ;;    pred:       2 [0.0%]  (FALSE_VALUE)
> ;;                5 (FALSE_VALUE)
>    # udiff.8_7 = PHI <0(2), udiff.8_8(5)>
>    _9 = &.paral_data_load.12_3->udiff.8D.2493;
>    # .MEM_34 = VDEF <.MEM_33(D)>
>    # USE = anything
>    # CLB = anything
>    __atomic_fetch_add_4D.1247 (_9, udiff.8_7, 0);
>    # VUSE <.MEM_34>
>    return;
> ;;    succ:       EXIT
>
> ;;   basic block 4, loop depth 0, count 0, freq 79, maybe hot
> ;;    prev block 3, next block 5, flags: (NEW, REACHABLE)
> ;;    pred:       2 [100.0%]  (TRUE_VALUE)
>    _10 = omp_get_num_threadsD.1287 ();
>    _11 = (unsigned int) _10;
>    _12 = omp_get_thread_numD.1286 ();
>    _13 = (unsigned int) _12;
>    .trip.13_14 = 0;
> ;;    succ:       5 [100.0%]  (FALLTHRU)
>
> ;;   basic block 5, loop depth 1, count 0, freq 79, maybe hot
> ;;    prev block 4, next block 6, flags: (NEW, REACHABLE)
> ;;    pred:       4 [100.0%]  (FALLTHRU)
> ;;                8 [100.0%]  (FALLTHRU)
>    # udiff.8_8 = PHI <0(4), udiff.8_15(8)>
>    # .trip.13_16 = PHI <.trip.13_14(4), .trip.13_17(8)>
>    _18 = _11 * .trip.13_16;
>    _19 = _13 + _18;
>    _20 = _19 + 1;
>    _21 = MIN_EXPR <_4, _20>;
>    if (_19 < _4)
>      goto <bb 6>;
>    else
>      goto <bb 3>;
> ;;    succ:       6 [100.0%]  (TRUE_VALUE)
> ;;                3 (FALSE_VALUE)
>
> ;;   basic block 6, loop depth 1, count 0, freq 79, maybe hot
> ;;    prev block 5, next block 7, flags: (NEW, REACHABLE)
> ;;    pred:       5 [100.0%]  (TRUE_VALUE)
>    ivtmp_22 = _19;
> ;;    succ:       7 [100.0%]  (FALLTHRU)
>
> ;;   basic block 7, loop depth 2, count 0, freq 7920, maybe hot
> ;;    prev block 6, next block 8, flags: (NEW, REACHABLE)
> ;;    pred:       6 [100.0%]  (FALLTHRU)
> ;;                7 [100.0%]  (TRUE_VALUE)
>    # udiff.8_23 = PHI <udiff.8_8(6), udiff.8_15(7)>
>    # ivtmp_24 = PHI <ivtmp_22(6), ivtmp_25(7)>
>    i.9_28 = (intD.6) ivtmp_24;
>    # VUSE <.MEM_33(D)>
>    _29 = *ub_5[i.9_28];
>    # VUSE <.MEM_33(D)>
>    _30 = *uc_6[i.9_28];
>    _31 = _29 - _30;
>    udiff.8_15 = udiff.8_23 + _31;
>    i.9_32 = i.9_28 + 1;
>    ivtmp_25 = ivtmp_24 + 1;
>    if (ivtmp_25 < _21)
>      goto <bb 7>;
>    else
>      goto <bb 8>;
> ;;    succ:       7 [100.0%]  (TRUE_VALUE)
> ;;                8 (FALSE_VALUE)
>
> ;;   basic block 8, loop depth 1, count 0, freq 0, maybe hot
> ;;    prev block 7, next block 1, flags: (NEW, REACHABLE)
> ;;    pred:       7 (FALSE_VALUE)
>    .trip.13_17 = .trip.13_16 + 1;
>    goto <bb 5>;
> ;;    succ:       5 [100.0%]  (FALLTHRU)
>
> }
> ...
>

OK for trunk?

This updated patch includes a test-case.

Thanks,
- Tom