public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug tree-optimization/101120] New: vn_reference_maybe_forwprop_address can take much compile-time
@ 2021-06-18 11:33 rguenth at gcc dot gnu.org
2021-06-18 11:33 ` [Bug tree-optimization/101120] " rguenth at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-06-18 11:33 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101120
Bug ID: 101120
Summary: vn_reference_maybe_forwprop_address can take much
compile-time
Product: gcc
Version: 11.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: rguenth at gcc dot gnu.org
Target Milestone: ---
For polyhedron doduc.f90 I see
tree FRE : 5.05 ( 47%) 0.03 ( 14%) 5.16 ( 46%)
5780k ( 3%)
with -Ofast -march=haswell
and
tree iv optimization : 4.99 ( 40%) 0.13 ( 33%) 5.28 ( 40%)
218M ( 51%)
with -Ofast
Resulting from the vectorizer generating chains of constant adds
(_1 = _2 + 8 + 8 + 8 + 8 spread across multiple stmts). There's duplicate
bugs for this around but a possible cheap mitigation would be to fold those
to create cheaper to walk use-def chains for the passes between vectorization
and the next forwprop pass.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/101120] vn_reference_maybe_forwprop_address can take much compile-time
2021-06-18 11:33 [Bug tree-optimization/101120] New: vn_reference_maybe_forwprop_address can take much compile-time rguenth at gcc dot gnu.org
@ 2021-06-18 11:33 ` rguenth at gcc dot gnu.org
2021-06-18 12:06 ` rguenth at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-06-18 11:33 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101120
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot gnu.org
Last reconfirmed| |2021-06-18
Ever confirmed|0 |1
Keywords| |compile-time-hog
Status|UNCONFIRMED |ASSIGNED
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I'll see to do that.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/101120] vn_reference_maybe_forwprop_address can take much compile-time
2021-06-18 11:33 [Bug tree-optimization/101120] New: vn_reference_maybe_forwprop_address can take much compile-time rguenth at gcc dot gnu.org
2021-06-18 11:33 ` [Bug tree-optimization/101120] " rguenth at gcc dot gnu.org
@ 2021-06-18 12:06 ` rguenth at gcc dot gnu.org
2021-06-21 13:02 ` cvs-commit at gcc dot gnu.org
2021-06-21 13:03 ` rguenth at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-06-18 12:06 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101120
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 51034
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51034&action=edit
patch
That fixes the attached but we also have loads of dead loads around which
exposes
the IV opts issue at -Ofast where IVOPTs analyzes all the dead loads
with zero-use LHS. While we have
PUSH_INSERT_PASSES_WITHIN (pass_vectorize)
NEXT_PASS (pass_dce);
POP_INSERT_PASSES ()
there's no such attempt after SLP passes.
But pruning the DR chain after SLP permute is possible as another hack.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/101120] vn_reference_maybe_forwprop_address can take much compile-time
2021-06-18 11:33 [Bug tree-optimization/101120] New: vn_reference_maybe_forwprop_address can take much compile-time rguenth at gcc dot gnu.org
2021-06-18 11:33 ` [Bug tree-optimization/101120] " rguenth at gcc dot gnu.org
2021-06-18 12:06 ` rguenth at gcc dot gnu.org
@ 2021-06-21 13:02 ` cvs-commit at gcc dot gnu.org
2021-06-21 13:03 ` rguenth at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-06-21 13:02 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101120
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:
https://gcc.gnu.org/g:0ad9c7087ef3904da89f2db6007b6d28b116087f
commit r12-1699-g0ad9c7087ef3904da89f2db6007b6d28b116087f
Author: Richard Biener <rguenther@suse.de>
Date: Fri Jun 18 14:07:00 2021 +0200
tree-optimization/101120 - fix compile-time issue with SLP groups
This places two hacks to avoid an old compile-time issue when
vectorizing large permuted SLP groups with gaps where we end up
emitting loads and IV adjustments for the gap as well and those
have quite a high cost until they are eventually cleaned up.
The first hack is to fold the auto-inc style IV updates early
in the vectorizer rather than in the next forwprop pass which
shortens the SSA use-def chains of the used IV.
The second hack is to remove the unused loads after we've picked
all that we possibly use.
2021-06-18 Richard Biener <rguenther@suse.de>
PR tree-optimization/101120
* tree-vect-data-refs.c (bump_vector_ptr): Fold the
built increment.
* tree-vect-slp.c (vect_transform_slp_perm_load): Add
DR chain DCE capability.
* tree-vectorizer.h (vect_transform_slp_perm_load): Adjust.
* tree-vect-stmts.c (vectorizable_load): Remove unused
loads in the DR chain for SLP.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/101120] vn_reference_maybe_forwprop_address can take much compile-time
2021-06-18 11:33 [Bug tree-optimization/101120] New: vn_reference_maybe_forwprop_address can take much compile-time rguenth at gcc dot gnu.org
` (2 preceding siblings ...)
2021-06-21 13:02 ` cvs-commit at gcc dot gnu.org
@ 2021-06-21 13:03 ` rguenth at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-06-21 13:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101120
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-06-21 13:03 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-18 11:33 [Bug tree-optimization/101120] New: vn_reference_maybe_forwprop_address can take much compile-time rguenth at gcc dot gnu.org
2021-06-18 11:33 ` [Bug tree-optimization/101120] " rguenth at gcc dot gnu.org
2021-06-18 12:06 ` rguenth at gcc dot gnu.org
2021-06-21 13:02 ` cvs-commit at gcc dot gnu.org
2021-06-21 13:03 ` rguenth at gcc dot gnu.org
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).