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* [Bug tree-optimization/39557] New: Invalid PDOM lead to infinite loop to be generated
@ 2009-03-25 23:09 davidxl at gcc dot gnu dot org
2009-03-25 23:10 ` [Bug tree-optimization/39557] " davidxl at gcc dot gnu dot org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: davidxl at gcc dot gnu dot org @ 2009-03-25 23:09 UTC (permalink / raw)
To: gcc-bugs
Compiling the attached source with the following options
-Wall -fno-exceptions -O2 -fprofile-use=/blah -fno-rtti
will result in a code with infinite loop.
In DCE, special code is added to handle dead loops conservatively. However this
requires PDOM information (control dep info) to be valid. The PDOM is created
in unintialized variable warning, but gets invalidated before cddce pass (the
incremental update does not work well). With the wrong CD info, DCE pass tries
to eliminate the loop, but the exit edge fixup code ends up linking the
precessor not to its post-dom bb, but to itself -- leading to infinite loop.
A proposed patch will be posted to gcc-patches.
David
--
Summary: Invalid PDOM lead to infinite loop to be generated
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: davidxl at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39557
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/39557] Invalid PDOM lead to infinite loop to be generated
2009-03-25 23:09 [Bug tree-optimization/39557] New: Invalid PDOM lead to infinite loop to be generated davidxl at gcc dot gnu dot org
@ 2009-03-25 23:10 ` davidxl at gcc dot gnu dot org
2009-03-27 18:26 ` davidxl at gcc dot gnu dot org
2009-03-27 20:21 ` rguenth at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: davidxl at gcc dot gnu dot org @ 2009-03-25 23:10 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from davidxl at gcc dot gnu dot org 2009-03-25 23:10 -------
Created an attachment (id=17542)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17542&action=view)
test case
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39557
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/39557] Invalid PDOM lead to infinite loop to be generated
2009-03-25 23:09 [Bug tree-optimization/39557] New: Invalid PDOM lead to infinite loop to be generated davidxl at gcc dot gnu dot org
2009-03-25 23:10 ` [Bug tree-optimization/39557] " davidxl at gcc dot gnu dot org
@ 2009-03-27 18:26 ` davidxl at gcc dot gnu dot org
2009-03-27 20:21 ` rguenth at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: davidxl at gcc dot gnu dot org @ 2009-03-27 18:26 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from davidxl at gcc dot gnu dot org 2009-03-27 18:25 -------
See SVN revision 145121 for the fix.
--
davidxl at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39557
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/39557] Invalid PDOM lead to infinite loop to be generated
2009-03-25 23:09 [Bug tree-optimization/39557] New: Invalid PDOM lead to infinite loop to be generated davidxl at gcc dot gnu dot org
2009-03-25 23:10 ` [Bug tree-optimization/39557] " davidxl at gcc dot gnu dot org
2009-03-27 18:26 ` davidxl at gcc dot gnu dot org
@ 2009-03-27 20:21 ` rguenth at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2009-03-27 20:21 UTC (permalink / raw)
To: gcc-bugs
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |4.4.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39557
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2009-03-27 20:21 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2009-03-25 23:09 [Bug tree-optimization/39557] New: Invalid PDOM lead to infinite loop to be generated davidxl at gcc dot gnu dot org
2009-03-25 23:10 ` [Bug tree-optimization/39557] " davidxl at gcc dot gnu dot org
2009-03-27 18:26 ` davidxl at gcc dot gnu dot org
2009-03-27 20:21 ` rguenth at gcc dot gnu dot org
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