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* [Bug lto/47943] New: PRE fails to move a load before a loop with LTO
@ 2011-03-01 13:10 jamborm at gcc dot gnu.org
2011-03-01 13:11 ` [Bug lto/47943] " jamborm at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: jamborm at gcc dot gnu.org @ 2011-03-01 13:10 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47943
Summary: PRE fails to move a load before a loop with LTO
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: lto
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: jamborm@gcc.gnu.org
When compiling the provided testcase with LTO, PRE fails to hoist the
load of reg->node from the loop. Though this slows down the testcase
only marginally, it has a substantial performance impact for
462.libquantum from SPEC 2006.
When compiling the test case without LTO, PRE does move the load
before the loop.
Observed at least with trunk revision 170357 (2011-02-21), compiling
at -Ofast with and without -flto.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug lto/47943] PRE fails to move a load before a loop with LTO
2011-03-01 13:10 [Bug lto/47943] New: PRE fails to move a load before a loop with LTO jamborm at gcc dot gnu.org
@ 2011-03-01 13:11 ` jamborm at gcc dot gnu.org
2011-03-01 13:34 ` rguenth at gcc dot gnu.org
2011-03-02 0:45 ` jamborm at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: jamborm at gcc dot gnu.org @ 2011-03-01 13:11 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47943
--- Comment #1 from Martin Jambor <jamborm at gcc dot gnu.org> 2011-03-01 13:11:23 UTC ---
Created attachment 23499
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23499
Testcase
The testcase.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug lto/47943] PRE fails to move a load before a loop with LTO
2011-03-01 13:10 [Bug lto/47943] New: PRE fails to move a load before a loop with LTO jamborm at gcc dot gnu.org
2011-03-01 13:11 ` [Bug lto/47943] " jamborm at gcc dot gnu.org
@ 2011-03-01 13:34 ` rguenth at gcc dot gnu.org
2011-03-02 0:45 ` jamborm at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2011-03-01 13:34 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47943
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |WAITING
Last reconfirmed| |2011.03.01 13:34:01
Ever Confirmed|0 |1
--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-03-01 13:34:01 UTC ---
I think this is a dup of PR47924 as I now get
<bb 7>:
pretmp.8_39 = reg_3(D)->node;
pretmp.10_19 = 1 << control2_20(D);
pretmp.10_42 = 1 << control1_10(D);
pretmp.10_43 = pretmp.10_19 | pretmp.10_42;
<bb 3>:
# i_17 = PHI <i_37(10), 0(7)>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug lto/47943] PRE fails to move a load before a loop with LTO
2011-03-01 13:10 [Bug lto/47943] New: PRE fails to move a load before a loop with LTO jamborm at gcc dot gnu.org
2011-03-01 13:11 ` [Bug lto/47943] " jamborm at gcc dot gnu.org
2011-03-01 13:34 ` rguenth at gcc dot gnu.org
@ 2011-03-02 0:45 ` jamborm at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: jamborm at gcc dot gnu.org @ 2011-03-02 0:45 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47943
Martin Jambor <jamborm at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|WAITING |RESOLVED
Resolution| |DUPLICATE
--- Comment #3 from Martin Jambor <jamborm at gcc dot gnu.org> 2011-03-02 00:45:15 UTC ---
Indeed. And libquantum is now as fast as the non-LTO one (again). Thanks.
*** This bug has been marked as a duplicate of bug 47924 ***
^ permalink raw reply [flat|nested] 4+ messages in thread
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2011-03-01 13:10 [Bug lto/47943] New: PRE fails to move a load before a loop with LTO jamborm at gcc dot gnu.org
2011-03-01 13:11 ` [Bug lto/47943] " jamborm at gcc dot gnu.org
2011-03-01 13:34 ` rguenth at gcc dot gnu.org
2011-03-02 0:45 ` jamborm at gcc dot gnu.org
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