https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103192
--- Comment #6 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
Hmm, all these threads look correct. Following are my steps for verification.
In a stage2 compiler I do:
$ rm -f gimplify.o
$ make cc1 CXXFLAGS="-O2 -fdisable-tree-threadfull2 -fdisable-tree-threadfull1
-fdisable-tree-thread2 -fdisable-tree-thread1
-fdbg-cnt=registered_jump_thread:543-543:544-544:550-550:551-551:552-552:553-553:554-554:555-555
-fdump-tree-all-details --param=threader-debug=all"
$ ./cc1 a.c -O2 -fopenmp -quiet
a.c: In function ‘foo’:
a.c:35:13: internal compiler error: Segmentation fault
...
...
This disables all the threaders except DOM and ethread. It also splits up the
individual threaded paths for easy grepping in the source (dbgcnt.*543,
dbgcnt.*544, etc). All of the threads are needed to reproduce. All of them
are from ethread and belong to the gimplify_scan_omp_clauses function:
$ grep Register.*jump gimplify.c.*
gimplify.c.034t.ethread: [543] Registering jump thread: (687, 689) incoming
edge; (689, 690) nocopy;
gimplify.c.034t.ethread: [544] Registering jump thread: (688, 689) incoming
edge; (689, 693) nocopy;
gimplify.c.034t.ethread: [550] Registering jump thread: (776, 777) incoming
edge; (777, 801) nocopy;
gimplify.c.034t.ethread: [551] Registering jump thread: (779, 780) incoming
edge; (780, 781) nocopy;
gimplify.c.034t.ethread: [552] Registering jump thread: (780, 782) incoming
edge; (782, 785) nocopy;
gimplify.c.034t.ethread: [553] Registering jump thread: (784, 786) incoming
edge; (786, 787) nocopy;
gimplify.c.034t.ethread: [554] Registering jump thread: (785, 786) incoming
edge; (786, 788) nocopy;
gimplify.c.034t.ethread: [555] Registering jump thread: (804, 806) incoming
edge; (806, 807) nocopy;
All of these paths, with the exception of 551 are trivially solvable. For
example:
The IL immediate above this...
***dbgcnt: lower limit 543 reached for registered_jump_thread.***
***dbgcnt: upper limit 543 reached for registered_jump_thread.***
[543] Registering jump thread: (687, 689) incoming edge; (689, 690) nocopy;
path: 687->689->690 SUCCESS
...is the path:
<bb 689> :
# iftmp.2344_1598 = PHI <1(687), 0(688)>
if (iftmp.2344_1598 != 0)
goto <bb 690>; [INV]
else
goto <bb 693>; [INV]
That's an obvious thread from 687->689->690.
The rest are a similar pattern. The only different path is:
***dbgcnt: lower limit 551 reached for registered_jump_thread.***
***dbgcnt: upper limit 551 reached for registered_jump_thread.***
[551] Registering jump thread: (779, 780) incoming edge; (780, 781) nocopy;
path: 779->780->781 SUCCESS
with an IL of:
<bb 780> :
# iftmp.2373_1603 = PHI <outer_ctx_1871(778), ctx_1868(779)>
if (iftmp.2373_1603 != 0B)
goto <bb 781>; [INV]
else
goto <bb 782>; [INV]
but if you look at the definition of ctx_1868, it's clear it's threadable to
bb781 because ctx_1868 is known to be non-zero:
ctx_1868 = new_omp_context (region_type_1866(D));
ctx_1868->code = code_1869(D);
Those are all the jump threads in play and they're all correct.
