* [Bug tree-optimization/59249] Jump threading makes if-conversion and following vectorization impossible.
[not found] <bug-59249-4@http.gcc.gnu.org/bugzilla/>
@ 2013-11-22 12:56 ` rguenth at gcc dot gnu.org
2013-11-22 13:02 ` [Bug tree-optimization/59249] if-conversion doesn't handle basic-blocks with only critical predecessor edges rguenth at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2013-11-22 12:56 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59249
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2013-11-22
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Btw, the issue is that we only have critical predecessors for inserting code
on.
The fix is to re-organize if-conversion to either split a random edge when
that happens or to re-organize it to compute edge predicates rather than
basic-block predicates.
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug tree-optimization/59249] if-conversion doesn't handle basic-blocks with only critical predecessor edges
[not found] <bug-59249-4@http.gcc.gnu.org/bugzilla/>
2013-11-22 12:56 ` [Bug tree-optimization/59249] Jump threading makes if-conversion and following vectorization impossible rguenth at gcc dot gnu.org
@ 2013-11-22 13:02 ` rguenth at gcc dot gnu.org
2013-11-25 14:31 ` bmei at broadcom dot com
` (2 subsequent siblings)
4 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2013-11-22 13:02 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59249
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Btw, see PR57521 for how the code is different from that on the 4.8 branch.
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug tree-optimization/59249] if-conversion doesn't handle basic-blocks with only critical predecessor edges
[not found] <bug-59249-4@http.gcc.gnu.org/bugzilla/>
2013-11-22 12:56 ` [Bug tree-optimization/59249] Jump threading makes if-conversion and following vectorization impossible rguenth at gcc dot gnu.org
2013-11-22 13:02 ` [Bug tree-optimization/59249] if-conversion doesn't handle basic-blocks with only critical predecessor edges rguenth at gcc dot gnu.org
@ 2013-11-25 14:31 ` bmei at broadcom dot com
2013-11-26 11:48 ` bmei at broadcom dot com
2021-12-12 10:52 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 5+ messages in thread
From: bmei at broadcom dot com @ 2013-11-25 14:31 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59249
--- Comment #3 from Bingfeng Mei <bmei at broadcom dot com> ---
Richard, I am not sure I understand about how to split edge.
BB4
/ \
/ \
BB5 |
|\ |
| \ |
| \ |
| BB6
| /
| /
BB7
Compiler (HEAD) complains "only critical predecessors of BB6" (its predcessor
BB5 has more than one successor). Do you suggest to split edge between BB5 &
BB6 and insert an empty BB?
In the email thread, you blame poor implementation of tree-level if-conversion.
But RTL-level CE passes cannot handle that too.
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug tree-optimization/59249] if-conversion doesn't handle basic-blocks with only critical predecessor edges
[not found] <bug-59249-4@http.gcc.gnu.org/bugzilla/>
` (2 preceding siblings ...)
2013-11-25 14:31 ` bmei at broadcom dot com
@ 2013-11-26 11:48 ` bmei at broadcom dot com
2021-12-12 10:52 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 5+ messages in thread
From: bmei at broadcom dot com @ 2013-11-26 11:48 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59249
--- Comment #4 from Bingfeng Mei <bmei at broadcom dot com> ---
Even I split one critical predecessor edge, predicate of BB6 is still ORed
result of two conditions from BB4 & BB5. ORing two conditions results in a
sequence of statements that cannot be vectorized. Vectorizer complains of
"bit-precision arithmetic not supported" because of boolean operations.
Not sure how to transform the code except reverting back to a form similar to
pre jump-threading.
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug tree-optimization/59249] if-conversion doesn't handle basic-blocks with only critical predecessor edges
[not found] <bug-59249-4@http.gcc.gnu.org/bugzilla/>
` (3 preceding siblings ...)
2013-11-26 11:48 ` bmei at broadcom dot com
@ 2021-12-12 10:52 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-12 10:52 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59249
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
See Also| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=56541
Known to work| |7.1.0
Known to fail|7.1.0 |6.1.0
Resolution|--- |FIXED
Target Milestone|--- |7.0
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed in GCC 7, I suspect by r7-529-g1cfcd39eee915a758 (aka PR 56541).
^ permalink raw reply [flat|nested] 5+ messages in thread