* [Bug tree-optimization/102794] [12 Regression] missing vrp in evrp dealing with casts and ands
2021-10-16 4:49 [Bug tree-optimization/102794] New: [12 Regression] missing vrp in evrp dealing with casts and ands pinskia at gcc dot gnu.org
@ 2021-10-16 4:50 ` pinskia at gcc dot gnu.org
2021-10-16 5:01 ` pinskia at gcc dot gnu.org
` (3 subsequent siblings)
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From: pinskia at gcc dot gnu.org @ 2021-10-16 4:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102794
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |12.0
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug tree-optimization/102794] [12 Regression] missing vrp in evrp dealing with casts and ands
2021-10-16 4:49 [Bug tree-optimization/102794] New: [12 Regression] missing vrp in evrp dealing with casts and ands pinskia at gcc dot gnu.org
2021-10-16 4:50 ` [Bug tree-optimization/102794] " pinskia at gcc dot gnu.org
@ 2021-10-16 5:01 ` pinskia at gcc dot gnu.org
2021-10-16 7:07 ` aldyh at redhat dot com
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From: pinskia at gcc dot gnu.org @ 2021-10-16 5:01 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102794
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |aldyh at gcc dot gnu.org
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Jump threading really messes up the loop here ...
about to thread: path: 4 -> 6, 6 -> 7, 7 -> 3,
just threaded: path: 4 -> 9, 6 -> 7, 7 -> 3,
I don't know what else to say. Maybe move ethread after evpr?
Note with -fno-thread-jumps, evpr is able to figure out the induction variable
goes from [-100, -1] . It does look like jump threading is full on messing up
how induction variable detection works; we get two a = a +1; statement after
the jump threading improvements.
Maybe there is another bug about that case already.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug tree-optimization/102794] [12 Regression] missing vrp in evrp dealing with casts and ands
2021-10-16 4:49 [Bug tree-optimization/102794] New: [12 Regression] missing vrp in evrp dealing with casts and ands pinskia at gcc dot gnu.org
2021-10-16 4:50 ` [Bug tree-optimization/102794] " pinskia at gcc dot gnu.org
2021-10-16 5:01 ` pinskia at gcc dot gnu.org
@ 2021-10-16 7:07 ` aldyh at redhat dot com
2021-10-16 7:35 ` pinskia at gcc dot gnu.org
2021-10-22 21:39 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: aldyh at redhat dot com @ 2021-10-16 7:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102794
--- Comment #2 from Aldy Hernandez <aldyh at redhat dot com> ---
I haven't looked at this, but there's a pending patch with more
restrictions for loop threading in the presence of loops. Does this help?
https://gcc.gnu.org/pipermail/gcc-patches/2021-October/581637.html
We really shouldn't be destroying loop info.
On Sat, Oct 16, 2021, 07:01 pinskia at gcc dot gnu.org <
gcc-bugzilla@gcc.gnu.org> wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102794
>
> Andrew Pinski <pinskia at gcc dot gnu.org> changed:
>
> What |Removed |Added
>
> ----------------------------------------------------------------------------
> CC| |aldyh at gcc dot gnu.org
>
> --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
> Jump threading really messes up the loop here ...
> about to thread: path: 4 -> 6, 6 -> 7, 7 -> 3,
> just threaded: path: 4 -> 9, 6 -> 7, 7 -> 3,
>
> I don't know what else to say. Maybe move ethread after evpr?
>
> Note with -fno-thread-jumps, evpr is able to figure out the induction
> variable
> goes from [-100, -1] . It does look like jump threading is full on
> messing up
> how induction variable detection works; we get two a = a +1; statement
> after
> the jump threading improvements.
> Maybe there is another bug about that case already.
>
> --
> You are receiving this mail because:
> You are on the CC list for the bug.
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/102794] [12 Regression] missing vrp in evrp dealing with casts and ands
2021-10-16 4:49 [Bug tree-optimization/102794] New: [12 Regression] missing vrp in evrp dealing with casts and ands pinskia at gcc dot gnu.org
` (2 preceding siblings ...)
2021-10-16 7:07 ` aldyh at redhat dot com
@ 2021-10-16 7:35 ` pinskia at gcc dot gnu.org
2021-10-22 21:39 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-10-16 7:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102794
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Aldy Hernandez from comment #2)
> I haven't looked at this, but there's a pending patch with more
> restrictions for loop threading in the presence of loops. Does this help?
>
> https://gcc.gnu.org/pipermail/gcc-patches/2021-October/581637.html
>
> We really shouldn't be destroying loop info.
Yes I think it does, though I have not tried it.
There was a jump threading here:
<bb 4> :
if (d_10 != 0)
goto <bb 5>; [INV]
else
goto <bb 6>; [INV]
<bb 5> :
foo ();
<bb 6> :
a_12 = a_3 + 1;
<bb 7> : ;;; loop header
# a_3 = PHI <-100(2), a_12(6)>
if (a_3 != 0)
goto <bb 3>; [INV]
else
goto <bb 8>; [INV]
where d_10 is defined as:
d_10 = (short unsigned int) a_3;
So yes blocking jumping through the loop header would help.
It is very similar to your f3 in ssa-thread-invalid.c testcase.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug tree-optimization/102794] [12 Regression] missing vrp in evrp dealing with casts and ands
2021-10-16 4:49 [Bug tree-optimization/102794] New: [12 Regression] missing vrp in evrp dealing with casts and ands pinskia at gcc dot gnu.org
` (3 preceding siblings ...)
2021-10-16 7:35 ` pinskia at gcc dot gnu.org
@ 2021-10-22 21:39 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-10-22 21:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102794
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|UNCONFIRMED |RESOLVED
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed most likely by r12-4526.
^ permalink raw reply [flat|nested] 6+ messages in thread