[Bug middle-end/81464] [8 Regression] ICE in expand_omp_for_static_chunk, at omp-expand.c:4236
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81464 --- Comment #8 from Tom de Vries --- Author: vries Date: Wed Jul 19 06:25:40 2017 New Revision: 250335 URL: https://gcc.gnu.org/viewcvs?rev=250335&root=gcc&view=rev Log: Handle equal-argument loop exit phi in expand_omp_for_static_chunk 2017-07-18 Tom de Vries PR middle-end/81464 * omp-expand.c (expand_omp_for_static_chunk): Handle equal-argument loop exit phi. * gfortran.dg/pr81464.f90: New test. Added: trunk/gcc/testsuite/gfortran.dg/pr81464.f90 Modified: trunk/gcc/ChangeLog trunk/gcc/omp-expand.c trunk/gcc/testsuite/ChangeLog
[Bug middle-end/81464] [8 Regression] ICE in expand_omp_for_static_chunk, at omp-expand.c:4236
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81464 Tom de Vries changed: What|Removed |Added Status|NEW |RESOLVED Component|web |middle-end Resolution|--- |FIXED --- Comment #7 from Tom de Vries --- Patch with test-case committed, marking resolved fixed.
[Bug middle-end/81464] [8 Regression] ICE in expand_omp_for_static_chunk, at omp-expand.c:4236
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81464 --- Comment #5 from Tom de Vries --- Created attachment 41779 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41779&action=edit Tentative patch
[Bug middle-end/81464] [8 Regression] ICE in expand_omp_for_static_chunk, at omp-expand.c:4236
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81464
--- Comment #4 from Tom de Vries ---
(In reply to Tom de Vries from comment #3)
> Tentative patch:
> ...
> diff --git a/gcc/omp-expand.c b/gcc/omp-expand.c
> index 929c530..089bffc 100644
> --- a/gcc/omp-expand.c
> +++ b/gcc/omp-expand.c
> @@ -4206,6 +4206,10 @@ expand_omp_for_static_chunk (struct omp_region
> *region,
> source_location locus;
>
> phi = psi.phi ();
> + if (operand_equal_p (gimple_phi_arg_def (phi, 0),
> + gimple_phi_arg_def (phi, 1), 0))
> + continue;
> +
> t = gimple_phi_result (phi);
> gcc_assert (t == redirect_edge_var_map_result (vm));
>
> ...
As it turns out, at the point of the operand_equal_p test, we already lost the
second argument of the phi.
I thought that this would trigger an assert, but apparently we don't have this:
...
@@ -4379,6 +4379,7 @@ phi_nodes_ptr (basic_block bb)
static inline tree
gimple_phi_arg_def (gimple *gs, size_t index)
{
+ gcc_gimple_checking_assert (index < gimple_phi_num_args(gs));
return gimple_phi_arg (gs, index)->def;
}
...
Using redirect_edge_var_map_def instead fixes this.
[Bug middle-end/81464] [8 Regression] ICE in expand_omp_for_static_chunk, at omp-expand.c:4236
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81464 --- Comment #3 from Tom de Vries --- Minimal example: ... program main implicit none real, dimension(:,:),allocatable :: a, b, c real :: sm allocate (a(2,2), b(2,2), c(2,2)) call random_number(a) call random_number(b) c = matmul(a,b) sm = sum(c) deallocate(a,b,c) end program main ... The assert happens in expand_omp_for_static_chunk when trying to expand a region from bb71 to bb72: ... (gdb) p region.entry.index $1 = 71 (gdb) p region.exit.index $2 = 72 ... In other words: ... ;; basic block 71, loop depth 0, freq 48, maybe hot ;;prev block 69, next block 67, flags: (NEW) ;;pred: 69 [always] (FALLTHRU) #pragma omp for schedule(static,2) for (ivtmp_87 = 0; ivtmp_87 < _144; ivtmp_87 = + 1) ;;succ: 67 [always] (FALLTHRU) ;;72 [never (guessed)] ... ;; basic block 72, loop depth 0, freq 47, maybe hot ;; Invalid sum of incoming frequencies 269, should be 47 ;;prev block 63, next block 70, flags: (NEW) ;;pred: 46 [always] (FALLTHRU) ;;71 [never (guessed)] # .MEM_88 = PHI <.MEM_86(46), .MEM_86(71)> #pragma omp return(nowait) ;;succ: 70 [always] (FALLTHRU) ... When we're ICE-ing, we're executing a bit: ... /* When we redirect the edge from trip_update_bb to iter_part_bb, we remove arguments of the phi nodes in fin_bb. We need to create appropriate phi nodes in iter_part_bb instead. */ ... When we look at fin_bb, we see indeed that one of the arguments of the phi has been dropped.: ... (gdb) call debug_bb (fin_bb) ;; basic block 72, loop depth 0, freq 47, maybe hot ;; prev block 100, next block 70, flags: (NEW) ;; pred: 98 [never (guessed)] (FALSE_VALUE) # .MEM_88 = PHI <.MEM_86(98)> ;; succ: 70 [always] (FALLTHRU) ... But since the arguments were equal anyway, this is fine, and there's no need to do anything. Tentative patch: ... diff --git a/gcc/omp-expand.c b/gcc/omp-expand.c index 929c530..089bffc 100644 --- a/gcc/omp-expand.c +++ b/gcc/omp-expand.c @@ -4206,6 +4206,10 @@ expand_omp_for_static_chunk (struct omp_region *region, source_location locus; phi = psi.phi (); + if (operand_equal_p (gimple_phi_arg_def (phi, 0), + gimple_phi_arg_def (phi, 1), 0)) + continue; + t = gimple_phi_result (phi); gcc_assert (t == redirect_edge_var_map_result (vm)); ...
[Bug middle-end/81464] [8 Regression] ICE in expand_omp_for_static_chunk, at omp-expand.c:4236
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81464 Richard Biener changed: What|Removed |Added Version|7.0 |8.0 Target Milestone|--- |8.0
[Bug middle-end/81464] [8 Regression] ICE in expand_omp_for_static_chunk, at omp-expand.c:4236
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81464 Jakub Jelinek changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2017-07-17 CC||vries at gcc dot gnu.org Ever confirmed|0 |1 --- Comment #2 from Jakub Jelinek --- CCing Tom as the author of r227437.
[Bug middle-end/81464] [8 Regression] ICE in expand_omp_for_static_chunk, at omp-expand.c:4236
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81464 Jakub Jelinek changed: What|Removed |Added CC||jakub at gcc dot gnu.org --- Comment #1 from Jakub Jelinek --- This is when searching for a PHI for vop .MEM_NNN, but apparently there is no such PHI. I'm afraid I'm not familiar with this part of code to know why it is trying to do that.
