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* [Bug middle-end/55863] New: Fails to fold (i + 2) - (i + 1) to 1
@ 2013-01-03 14:29 rguenth at gcc dot gnu.org
2013-01-03 14:29 ` [Bug middle-end/55863] " rguenth at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2013-01-03 14:29 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55863
Bug #: 55863
Summary: Fails to fold (i + 2) - (i + 1) to 1
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: rguenth@gcc.gnu.org
For
(analyze_overlapping_iterations
(chrec_a = {pretmp_1529 + 1, +, 1}_20)
(chrec_b = {pretmp_1529 + 2, +, 1}_20)
The SIV test currently fails because when computing the difference
between the CHRECs we compute pretmp_1529 + 2 + ~pretmp15_29. This
is because when computing A - B we check if B is easy to negate - which
X + 1 is - and compute it as A + ~X which association then fails to
optimize.
This makes dependence tests of this kind fail.
^ permalink raw reply [flat|nested] 4+ messages in thread* [Bug middle-end/55863] Fails to fold (i + 2) - (i + 1) to 1 2013-01-03 14:29 [Bug middle-end/55863] New: Fails to fold (i + 2) - (i + 1) to 1 rguenth at gcc dot gnu.org @ 2013-01-03 14:29 ` rguenth at gcc dot gnu.org 2013-01-04 10:46 ` rguenth at gcc dot gnu.org 2013-01-04 10:46 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2013-01-03 14:29 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55863 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |ASSIGNED Last reconfirmed| |2013-01-03 AssignedTo|unassigned at gcc dot |rguenth at gcc dot gnu.org |gnu.org | Ever Confirmed|0 |1 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> 2013-01-03 14:29:25 UTC --- I have a patch. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/55863] Fails to fold (i + 2) - (i + 1) to 1 2013-01-03 14:29 [Bug middle-end/55863] New: Fails to fold (i + 2) - (i + 1) to 1 rguenth at gcc dot gnu.org 2013-01-03 14:29 ` [Bug middle-end/55863] " rguenth at gcc dot gnu.org @ 2013-01-04 10:46 ` rguenth at gcc dot gnu.org 2013-01-04 10:46 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2013-01-04 10:46 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55863 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution| |FIXED --- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> 2013-01-04 10:46:31 UTC --- Fixed. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/55863] Fails to fold (i + 2) - (i + 1) to 1 2013-01-03 14:29 [Bug middle-end/55863] New: Fails to fold (i + 2) - (i + 1) to 1 rguenth at gcc dot gnu.org 2013-01-03 14:29 ` [Bug middle-end/55863] " rguenth at gcc dot gnu.org 2013-01-04 10:46 ` rguenth at gcc dot gnu.org @ 2013-01-04 10:46 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2013-01-04 10:46 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55863 --- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> 2013-01-04 10:45:44 UTC --- Author: rguenth Date: Fri Jan 4 10:45:37 2013 New Revision: 194899 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=194899 Log: 2013-01-04 Richard Biener <rguenther@suse.de> PR middle-end/55863 * fold-const.c (split_tree): Undo -X - 1 to ~X folding for reassociation. * gcc.dg/fold-reassoc-2.c: New testcase. Added: trunk/gcc/testsuite/gcc.dg/fold-reassoc-2.c Modified: trunk/gcc/ChangeLog trunk/gcc/fold-const.c trunk/gcc/testsuite/ChangeLog ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2013-01-04 10:46 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2013-01-03 14:29 [Bug middle-end/55863] New: Fails to fold (i + 2) - (i + 1) to 1 rguenth at gcc dot gnu.org 2013-01-03 14:29 ` [Bug middle-end/55863] " rguenth at gcc dot gnu.org 2013-01-04 10:46 ` rguenth at gcc dot gnu.org 2013-01-04 10:46 ` rguenth at gcc dot gnu.org
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