On Thu, Mar 23, 2017 at 7:20 PM, Bill Schmidt
<wschm...@linux.vnet.ibm.com> wrote:
> Hi,
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80158 reports an ICE in
> SLSR while building 416.gamess on x86_64. This is a latent (but
> previously harmless) bug that was exposed by the fix for PR80054.
> When replacing any statement with a strength reduction, SLSR updates
> the candidate statement S associated with the associated candidate
> record in the candidate table. However, S may actually be associated
> with two candidate records when an expression may be treated as
> either a CAND_ADD or a CAND_MULT. In this case, the second one can
> be reached via the next_interp field.
Hmm, the following code in SLSR suggests there may be more than
one such alternate candidate:
while (arg_cand->kind != CAND_ADD && arg_cand->kind != CAND_PHI)
{
if (!arg_cand->next_interp)
return;
arg_cand = lookup_cand (arg_cand->next_interp);
}
> In the excerpt from 416.gamess, the first candidate record was
> updated when its statement was replaced, but the next-interp record
> was not. Later, that record was used as a basis for another tree
> of strength-reduction candidates, but since it now pointed to an
> orphaned statement without a basic block, the ICE occurred when
> checking dominance against the statement's block.
>
> The fix is simply to ensure that the next_interp record is always
> updated when present.
>
> I've bootstrapped and tested this on powerpc64le-unknown-linux-gnu
> with no regressions. I tested that the standalone test works on
> x86_64 with this fix, but I have been unable to perform an x86_64
> regstrap because the machine I have access to has insufficient
> disk space. :/ I would appreciate it if you could do this for me.
>
> Assuming no problems with x86_64 regstrap, is this ok for trunk?
>
> Note: I will be unreachable from now until next Tuesday (i.e.,
> returning the 28th). If needed, please feel free to commit the
> patch on my behalf. Otherwise I will attend to it when I return.
I'll do a regstrap and gamess build and will commit if that succeeds.
The above can be addressed as followup.
Thanks,
Richard.
> Thanks!
> Bill
>
>
> [gcc]
>
> 2017-03-23 Bill Schmidt <wschm...@linux.vnet.ibm.com>
>
> PR tree-optimization/80158
> * gimple-ssa-strength-reduction.c (replace_mult_candidate): When
> replacing a candidate statement, also replace it for the
> candidate's alternate interpretation.
> (replace_rhs_if_not_dup): Likewise.
> (replace_one_candidate): Likewise.
>
> [gcc/testsuite]
>
> 2017-03-23 Bill Schmidt <wschm...@linux.vnet.ibm.com>
>
> PR tree-optimization/80158
> * gfortran.fortran-torture/compile/pr80158.f: New file.
>
>
> Index: gcc/gimple-ssa-strength-reduction.c
> ===================================================================
> --- gcc/gimple-ssa-strength-reduction.c (revision 246420)
> +++ gcc/gimple-ssa-strength-reduction.c (working copy)
> @@ -2089,6 +2089,8 @@ replace_mult_candidate (slsr_cand_t c, tree basis_
> gimple_set_location (copy_stmt, gimple_location (c->cand_stmt));
> gsi_replace (&gsi, copy_stmt, false);
> c->cand_stmt = copy_stmt;
> + if (c->next_interp)
> + lookup_cand (c->next_interp)->cand_stmt = copy_stmt;
> if (dump_file && (dump_flags & TDF_DETAILS))
> stmt_to_print = copy_stmt;
> }
> @@ -2118,6 +2120,8 @@ replace_mult_candidate (slsr_cand_t c, tree basis_
> basis_name, bump_tree);
> update_stmt (gsi_stmt (gsi));
> c->cand_stmt = gsi_stmt (gsi);
> + if (c->next_interp)
> + lookup_cand (c->next_interp)->cand_stmt = gsi_stmt (gsi);
> if (dump_file && (dump_flags & TDF_DETAILS))
> stmt_to_print = gsi_stmt (gsi);
> }
> @@ -3405,6 +3409,8 @@ replace_rhs_if_not_dup (enum tree_code new_code, t
> gimple_assign_set_rhs_with_ops (&gsi, new_code, new_rhs1, new_rhs2);
> update_stmt (gsi_stmt (gsi));
> c->cand_stmt = gsi_stmt (gsi);
> + if (c->next_interp)
> + lookup_cand (c->next_interp)->cand_stmt = gsi_stmt (gsi);
>
> if (dump_file && (dump_flags & TDF_DETAILS))
> return gsi_stmt (gsi);
> @@ -3511,6 +3517,8 @@ replace_one_candidate (slsr_cand_t c, unsigned i,
> gimple_assign_set_rhs_with_ops (&gsi, MINUS_EXPR, basis_name, rhs2);
> update_stmt (gsi_stmt (gsi));
> c->cand_stmt = gsi_stmt (gsi);
> + if (c->next_interp)
> + lookup_cand (c->next_interp)->cand_stmt = gsi_stmt (gsi);
>
> if (dump_file && (dump_flags & TDF_DETAILS))
> stmt_to_print = gsi_stmt (gsi);
> @@ -3532,6 +3540,8 @@ replace_one_candidate (slsr_cand_t c, unsigned i,
> gimple_set_location (copy_stmt, gimple_location (c->cand_stmt));
> gsi_replace (&gsi, copy_stmt, false);
> c->cand_stmt = copy_stmt;
> + if (c->next_interp)
> + lookup_cand (c->next_interp)->cand_stmt = copy_stmt;
>
> if (dump_file && (dump_flags & TDF_DETAILS))
> stmt_to_print = copy_stmt;
> @@ -3543,6 +3553,8 @@ replace_one_candidate (slsr_cand_t c, unsigned i,
> gimple_set_location (cast_stmt, gimple_location (c->cand_stmt));
> gsi_replace (&gsi, cast_stmt, false);
> c->cand_stmt = cast_stmt;
> + if (c->next_interp)
> + lookup_cand (c->next_interp)->cand_stmt = cast_stmt;
>
> if (dump_file && (dump_flags & TDF_DETAILS))
> stmt_to_print = cast_stmt;
> Index: gcc/testsuite/gfortran.fortran-torture/compile/pr80158.f
> ===================================================================
> --- gcc/testsuite/gfortran.fortran-torture/compile/pr80158.f (nonexistent)
> +++ gcc/testsuite/gfortran.fortran-torture/compile/pr80158.f (working copy)
> @@ -0,0 +1,16 @@
> + SUBROUTINE DRPAUL(SMAT,TMAT,EPS,EPT,SIJ,TIJ,WRK,VEC,ARRAY,FMO,
> + * XMKVIR,TMJ,XMI,YMI,ZMI,ZQQ,L1,L1EF,LNA,LNA2,
> + * NAEF,L2,NLOC,NVIR,PROVEC,FOCKMA,MXBF,MXMO2)
> + DIMENSION CMO(L1,L1),TLOC(LNA,LNA),SMJ(L1,NAEF),XMK(L1,LNA)
> + DO I = 1,LNA
> + DO J = 1,LNA
> + IF (I.LE.NOUT) TLOC(I,J) = ZERO
> + IF (J.LE.NOUT) TLOC(I,J) = ZERO
> + END DO
> + DO NA=1,NOC
> + IF ( ABS(E(NI)-E(NA)) .GE.TOL) THEN
> + END IF
> + END DO
> + END DO
> + END
> +
>
