This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: Fix PR middle-end/57370


On Fri, Sep 6, 2013 at 12:05 AM, Richard Biener
<richard.guenther@gmail.com> wrote:
> On Thu, Sep 5, 2013 at 9:23 PM, Easwaran Raman <eraman@google.com> wrote:
>> On Tue, Aug 27, 2013 at 3:35 AM, Richard Biener
>> <richard.guenther@gmail.com> wrote:
>>> On Thu, Aug 1, 2013 at 1:34 AM, Easwaran Raman <eraman@google.com> wrote:
>>>> I have a new patch that supersedes this. The new patch also fixes PR
>>>> tree-optimization/57393 and PR tree-optimization/58011. Bootstraps and
>>>> no test regression on x86_64/linux. Ok for trunk?
>>>>
>>>> 2013-07-31  Easwaran Raman  <eraman@google.com>
>>>>
>>>>     PR middle-end/57370
>>>>     * tree-ssa-reassoc.c (build_and_add_sum): Fix UID assignment and reset
>>>>     of debug statements that cause inconsistent IR.
>>>
>>> Missing ChangeLog entry for the insert_stmt_after hunk which I do not like
>>> at all.  The other hunks are ok, but we need to work harder to preserve
>>> debug stmts - simply removing all is not going to fly.
>>>
>>> Richard.
>>
>> I looked into the problem related to the debug stmts in this failing
>> test case in detail. Initially, the code sequence looks
>>
>>
>> s$n_13 = MEM[(struct S *)&s];
>> # DEBUG s$n => s$n_13
>> _2 = (double) s$n_13;
>> _4 = _2 * a_3(D);
>> _6 = (double) i_5(D);
>> _7 = _4 * _6;
>> _9 = (double) j_8(D);
>> _10 = _7 * _9;
>> bar (_10);
>> # DEBUG D#2 => (double) k_12(D)
>> # DEBUG D#1 => _7 * D#2
>> # DEBUG t$n => (int) D#1
>>
>> After reassociation
>>
>> s$n_13 = MEM[(struct S *)&s];
>> # DEBUG s$n => s$n_13
>> _2 = (double) s$n_13;
>> _6 = (double) i_5(D);
>> # DEBUG D#3 => _4 * _6
>> _9 = (double) j_8(D);
>> _4 = _9 * _2;
>> _7 = _4 * a_3(D);
>> _10 = _7 * _6;
>> bar (_10);
>> # DEBUG D#2 => (double) k_12(D)
>> # DEBUG D#1 => D#3 * D#2
>> # DEBUG t$n => (int) D#1
>>
>> In the above, # DEBUG D#3 => _4 * _6  appears above the statement that
>> defines _4. But even if I move the def of D#3 below the statement
>> defining _4, it is not sufficient. Before reassociation, t$n refers to
>> the expression (s$n_13 * a_3(D) * i_5(D) * k_12(D)), but after
>> reassociation it would refer to ( j_8(D) * s$n_13 *  i_5(D) *
>> k_12(D)). It seems the correct fix is to discard the debug temps whose
>> RHS contains a variable that is involved in reassociation and then
>> reconstruct it. Is that the expected fix here?
>
> The value of the DEBUG expression changes because the value
> that _4 computes changes - that is a no-no that may not happen.
> We cannot re-use _4 (without previously releasing it and allocating
> it newly) with a new value.  releasing _4 should have fixed up the
> debug stmts.
>
> So - can you verify whether we are indeed just replacing the
> RHS of _4 = _2 * a_3(D) to _9 * _2 without changing the SSA name of
> that expression?

I have confirmed that the SSA name of the LHS remains the same. The
reassociation code simply calls gimple_assign_set_rhs2 to modify RHS2
and then calls update_stmt.

- Easwaran

> Another reason why re-using the same LHS for another value is
> wrong is that annotated information like points-to sets, alignment
> and soon value-range information will be wrong.
>
> Thanks,
> Richard.
>
>> - Easwaran
>>
>>>>
>>>> testsuite/ChangeLog:
>>>> 2013-07-31  Easwaran Raman  <eraman@google.com>
>>>>
>>>>     PR middle-end/57370
>>>>     PR tree-optimization/57393
>>>>     PR tree-optimization/58011
>>>>     * gfortran.dg/reassoc_12.f90: New testcase.
>>>>     * gcc.dg/tree-ssa/reassoc-31.c: New testcase.
>>>>     * gcc.dg/tree-ssa/reassoc-31.c: New testcase.
>>>>
>>>>
>>>> On Fri, Jul 12, 2013 at 7:57 AM, Easwaran Raman <eraman@google.com> wrote:
>>>>> Ping.
>>>>>
>>>>> On Thu, Jun 27, 2013 at 10:15 AM, Easwaran Raman <eraman@google.com> wrote:
>>>>>> A newly generated statement in build_and_add_sum  function of
>>>>>> tree-ssa-reassoc.c has to be assigned the UID of its adjacent
>>>>>> statement. In one instance, it was assigned the wrong uid (of an
>>>>>> earlier phi statement) which messed up the IR and caused the test
>>>>>> program to hang. Bootstraps and no test regressions on x86_64/linux.
>>>>>> Ok for trunk?
>>>>>>
>>>>>> Thanks,
>>>>>> Easwaran
>>>>>>
>>>>>>
>>>>>> 2013-06-27  Easwaran Raman  <eraman@google.com>
>>>>>>
>>>>>>         PR middle-end/57370
>>>>>>         * tree-ssa-reassoc.c (build_and_add_sum): Do not use the UID of a phi
>>>>>>         node for a non-phi gimple statement.
>>>>>>
>>>>>> testsuite/ChangeLog:
>>>>>> 2013-06-27  Easwaran Raman  <eraman@google.com>
>>>>>>
>>>>>>         PR middle-end/57370
>>>>>>         * gfortran.dg/reassoc_12.f90: New testcase.
>>>>>>
>>>>>>
>>>>>> Index: gcc/testsuite/gfortran.dg/reassoc_12.f90
>>>>>> ===================================================================
>>>>>> --- gcc/testsuite/gfortran.dg/reassoc_12.f90 (revision 0)
>>>>>> +++ gcc/testsuite/gfortran.dg/reassoc_12.f90 (revision 0)
>>>>>> @@ -0,0 +1,74 @@
>>>>>> +! { dg-do compile }
>>>>>> +! { dg-options "-O2 -ffast-math" }
>>>>>> +! PR middle-end/57370
>>>>>> +
>>>>>> + SUBROUTINE xb88_lr_adiabatic_lda_calc(e_ndrho_ndrho_ndrho, &
>>>>>> +                                       grad_deriv,npoints, sx)
>>>>>> +    IMPLICIT REAL*8 (t)
>>>>>> +    INTEGER, PARAMETER :: dp=8
>>>>>> +    REAL(kind=dp), DIMENSION(1:npoints) :: e_ndrho_ndrho_ndrho, &
>>>>>> +                                           e_ndrho_ndrho_rho
>>>>>> +      DO ii=1,npoints
>>>>>> +          IF( grad_deriv >= 2 .OR. grad_deriv == -2 ) THEN
>>>>>> +            t1425 = t233 * t557
>>>>>> +            t1429 = beta * t225
>>>>>> +            t1622 = t327 * t1621
>>>>>> +            t1626 = t327 * t1625
>>>>>> +            t1632 = t327 * t1631
>>>>>> +            t1685 = t105 * t1684
>>>>>> +            t2057 = t1636 + t8 * (t2635 + t3288)
>>>>>> +          END IF
>>>>>> +          IF( grad_deriv >= 3 .OR. grad_deriv == -3 ) THEN
>>>>>> +            t5469 = t5440 - t5443 - t5446 - t5449 - &
>>>>>> +                    t5451 - t5454 - t5456 + t5459  - &
>>>>>> +                    t5462 + t5466 - t5468
>>>>>> +            t5478 = 0.240e2_dp * t1616 * t973 * t645 * t1425
>>>>>> +            t5489 = 0.1600000000e2_dp * t1429 * t1658
>>>>>> +            t5531 = 0.160e2_dp * t112 * t1626
>>>>>> +            t5533 = 0.160e2_dp * t112 * t1632
>>>>>> +            t5537 = 0.160e2_dp * t112 * t1622
>>>>>> +            t5541 = t5472 - t5478 - t5523 + t5525 + &
>>>>>> +                    t5531 + t5533 + t5535 + t5537 + &
>>>>>> +                    t5540
>>>>>> +            t5565 = t112 * t1685
>>>>>> +            t5575 = t5545 - t5548 + t5551 + t5553 - &
>>>>>> +                    t5558 + t5560 - t5562 + t5564 - &
>>>>>> +                    0.80e1_dp * t5565 + t5568 + t5572 + &
>>>>>> +                    t5574
>>>>>> +            t5611 = t5579 - t5585 + t5590 - t5595 + &
>>>>>> +                    t5597 - t5602 + t5604 + t5607 + &
>>>>>> +                    t5610
>>>>>> +            t5613 = t5469 + t5541 + t5575 + t5611
>>>>>> +            t6223 = t6189 - &
>>>>>> +                    0.3333333336e0_dp  * t83 * t84 * t5613 + &
>>>>>> +                    t6222
>>>>>> +            t6227 = - t8 * (t5305 + t6223)
>>>>>> +            e_ndrho_ndrho_rho(ii) = e_ndrho_ndrho_rho(ii) + &
>>>>>> +                     t6227 * sx
>>>>>> +            t6352 = t5440 - t5443 - t5446 - t5449 - &
>>>>>> +                    t5451 - t5454 + &
>>>>>> +                    0.40e1_dp * t102  * t327 * t2057 * t557 - &
>>>>>> +                    t5456 + t5459 - t5462 + t5466 - &
>>>>>> +                    t5468
>>>>>> +            t6363 = t5480 - t5489 + &
>>>>>> +                    0.9600000000e2_dp  * t1054 * t640 * t3679
>>>>>> +            t6367 = t5472 - t5474 - t5478 - t5523 + &
>>>>>> +                    t5525 + t5531 + t5533 + t5535 + &
>>>>>> +                    t5537 - 0.20e1_dp * t102 * t105 * t6363 + &
>>>>>> +                    t5540
>>>>>> +            t6370 = t5545 - t5548 + t5551 + t5553 - &
>>>>>> +                    t5558 + t5560 - t5562 + t5564  - &
>>>>>> +                    0.40e1_dp * t5565 + &
>>>>>> +                    t5568 + t5572 + t5574
>>>>>> +            t6373 = t5579 - t5585 + t5590 - t5595 + &
>>>>>> +                    t5597 - t5602 + t5604 + t5607 + &
>>>>>> +                    t5610
>>>>>> +            t6375 = t6352 + t6367 + t6370 + t6373
>>>>>> +            t6380 = - 0.3333333336e0_dp * t83 * t84 * t6375 + t5701
>>>>>> +            t6669 = -t4704 - t8 * (t6344 + t6380 + t6665)
>>>>>> +            e_ndrho_ndrho_ndrho(ii) = e_ndrho_ndrho_ndrho(ii) + &
>>>>>> +                     t6669 * sx
>>>>>> +          END IF
>>>>>> +      END DO
>>>>>> +  END SUBROUTINE xb88_lr_adiabatic_lda_calc
>>>>>> +
>>>>>> Index: gcc/tree-ssa-reassoc.c
>>>>>> ===================================================================
>>>>>> --- gcc/tree-ssa-reassoc.c        (revision 200429)
>>>>>> +++ gcc/tree-ssa-reassoc.c        (working copy)
>>>>>> @@ -1207,7 +1207,7 @@ build_and_add_sum (tree type, tree op1, tree op2,
>>>>>>        if (gimple_code (op1def) == GIMPLE_PHI)
>>>>>>          {
>>>>>>            gsi = gsi_after_labels (gimple_bb (op1def));
>>>>>> -           gimple_set_uid (sum, gimple_uid (op1def));
>>>>>> +          gimple_set_uid (sum, gimple_uid (gsi_stmt (gsi)));
>>>>>>            gsi_insert_before (&gsi, sum, GSI_NEW_STMT);
>>>>>>          }
>>>>>>        else


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]