* spaceship_replacement cannot see through simplified set of FP conditionals
@ 2022-07-29 11:40 Aldy Hernandez
2022-07-29 11:49 ` Jakub Jelinek
0 siblings, 1 reply; 4+ messages in thread
From: Aldy Hernandez @ 2022-07-29 11:40 UTC (permalink / raw)
To: Jakub Jelinek, GCC Mailing List
Hi.
With my upcoming patch enabling floating point VRP,
g++.dg/opt/pr94589-2.C is failing:
https://gcc.gnu.org/pipermail/gcc-patches/2022-July/598788.html
The problem is that phiopt no longer sees the following snippet,
because we have folded away the final conditional as true:
bool f5 (double i, double j)
{
signed char __v$_M_value;
signed char c$_M_value;
bool D.8519;
struct partial_ordering __v;
struct partial_ordering c;
unsigned int _11;
bool _16;
<bb 2> :
if (i_2(D) != j_4(D))
goto <bb 3>; [INV]
else
goto <bb 6>; [INV]
<bb 3> :
if (i_2(D) >= j_4(D))
goto <bb 4>; [INV]
else
goto <bb 6>; [INV]
<bb 4> :
if (i_2(D) > j_4(D))
goto <bb 6>; [INV]
else
goto <bb 5>; [INV]
<bb 5> :
<bb 6> :
# c$_M_value_3 = PHI <-1(3), 0(2), 2(5), 1(4)>
_11 = (unsigned int) c$_M_value_3;
_16 = _11 <= 1;
return _16;
}
This means that spaceship_replacement() now sees one less argument to the PHI:
<bb 2> :
if (i_2(D) != j_4(D))
goto <bb 3>; [INV]
else
goto <bb 5>; [INV]
<bb 3> :
if (i_2(D) >= j_4(D))
goto <bb 4>; [INV]
else
goto <bb 5>; [INV]
<bb 4> :
<bb 5> :
# c$_M_value_3 = PHI <-1(3), 0(2), 1(4)>
...and we bail because we are expecting 4 arguments:
if (EDGE_COUNT (phi_bb->preds) != 4)
return false;
Could someone give me a hand here? Can spaceship_replacement easily be
adapted to handle this case, or should we be simplifying this
elsewhere?
Thanks.
Aldy
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: spaceship_replacement cannot see through simplified set of FP conditionals
2022-07-29 11:40 spaceship_replacement cannot see through simplified set of FP conditionals Aldy Hernandez
@ 2022-07-29 11:49 ` Jakub Jelinek
2022-07-29 11:51 ` Aldy Hernandez
0 siblings, 1 reply; 4+ messages in thread
From: Jakub Jelinek @ 2022-07-29 11:49 UTC (permalink / raw)
To: Aldy Hernandez; +Cc: GCC Mailing List, MacLeod, Andrew
On Fri, Jul 29, 2022 at 01:40:12PM +0200, Aldy Hernandez wrote:
> With my upcoming patch enabling floating point VRP,
> g++.dg/opt/pr94589-2.C is failing:
>
> https://gcc.gnu.org/pipermail/gcc-patches/2022-July/598788.html
>
> The problem is that phiopt no longer sees the following snippet,
> because we have folded away the final conditional as true:
> Could someone give me a hand here? Can spaceship_replacement easily be
> adapted to handle this case, or should we be simplifying this
> elsewhere?
Leave it to me, once you commit, file a PR and I'll work on it.
Jakub
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: spaceship_replacement cannot see through simplified set of FP conditionals
2022-07-29 11:49 ` Jakub Jelinek
@ 2022-07-29 11:51 ` Aldy Hernandez
2022-07-29 11:57 ` Jakub Jelinek
0 siblings, 1 reply; 4+ messages in thread
From: Aldy Hernandez @ 2022-07-29 11:51 UTC (permalink / raw)
To: Jakub Jelinek; +Cc: GCC Mailing List, MacLeod, Andrew
Sweeeet!
Would you like me to XFAIL the test or leave it as a failure?
Thanks.
Aldy
On Fri, Jul 29, 2022 at 1:50 PM Jakub Jelinek <jakub@redhat.com> wrote:
>
> On Fri, Jul 29, 2022 at 01:40:12PM +0200, Aldy Hernandez wrote:
> > With my upcoming patch enabling floating point VRP,
> > g++.dg/opt/pr94589-2.C is failing:
> >
> > https://gcc.gnu.org/pipermail/gcc-patches/2022-July/598788.html
> >
> > The problem is that phiopt no longer sees the following snippet,
> > because we have folded away the final conditional as true:
>
> > Could someone give me a hand here? Can spaceship_replacement easily be
> > adapted to handle this case, or should we be simplifying this
> > elsewhere?
>
> Leave it to me, once you commit, file a PR and I'll work on it.
>
> Jakub
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: spaceship_replacement cannot see through simplified set of FP conditionals
2022-07-29 11:51 ` Aldy Hernandez
@ 2022-07-29 11:57 ` Jakub Jelinek
0 siblings, 0 replies; 4+ messages in thread
From: Jakub Jelinek @ 2022-07-29 11:57 UTC (permalink / raw)
To: Aldy Hernandez; +Cc: GCC Mailing List, MacLeod, Andrew
On Fri, Jul 29, 2022 at 01:51:00PM +0200, Aldy Hernandez wrote:
> Sweeeet!
>
> Would you like me to XFAIL the test or leave it as a failure?
Either is fine.
Jakub
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-07-29 11:58 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-07-29 11:40 spaceship_replacement cannot see through simplified set of FP conditionals Aldy Hernandez
2022-07-29 11:49 ` Jakub Jelinek
2022-07-29 11:51 ` Aldy Hernandez
2022-07-29 11:57 ` Jakub Jelinek
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).