[Bug tree-optimization/23838] [4.1/4.2 Regression] infinite loop in dse
--- Comment #2 from pinskia at gcc dot gnu dot org 2005-12-13 00:23 --- I am going to say this is 4.1 regression as it worked in 4.0.0 when removing the -fno-tree-copy-prop option but fails on the mainline and 4.1 branche with it. Somehow or another someone could come up with a testcase which fails also without any options which turn off optimizations (it is just harder to come up with one). -- pinskia at gcc dot gnu dot org changed: What|Removed |Added Summary|infinite loop in dse|[4.1/4.2 Regression] ||infinite loop in dse Target Milestone|--- |4.1.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23838
[Bug tree-optimization/23838] [4.1/4.2 Regression] infinite loop in dse
-- pinskia at gcc dot gnu dot org changed: What|Removed |Added Priority|P2 |P3 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23838
[Bug tree-optimization/23838] [4.1/4.2 Regression] infinite loop in dse
--- Comment #3 from law at redhat dot com 2005-12-15 02:53 --- Subject: Re: [4.1/4.2 Regression] infinite loop in dse On Tue, 2005-12-13 at 00:23 +, pinskia at gcc dot gnu dot org wrote: > > --- Comment #2 from pinskia at gcc dot gnu dot org 2005-12-13 00:23 > --- > I am going to say this is 4.1 regression as it worked in 4.0.0 when removing > the -fno-tree-copy-prop option but fails on the mainline and 4.1 branche with > it. Somehow or another someone could come up with a testcase which fails also > without any options which turn off optimizations (it is just harder to come up > with one). I just checked in the attached patch to the 4.1 branch. I'm testing the same patch for mainline now. Basically we had a PHI node which both used and defined the same SSA_NAME (which can only occur at the head of a loop where the SSA_NAME is an invariant and copies have not been fully propagated). The safe thing to do is not try and optimize this case. --- Comment #4 from law at redhat dot com 2005-12-15 02:54 --- Created an attachment (id=10491) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10491&action=view) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23838
[Bug tree-optimization/23838] [4.1/4.2 Regression] infinite loop in dse
--- Comment #5 from law at redhat dot com 2005-12-16 07:04 --- Subject: Re: [4.1/4.2 Regression] infinite loop in dse On Tue, 2005-12-13 at 00:23 +, pinskia at gcc dot gnu dot org wrote: > > --- Comment #2 from pinskia at gcc dot gnu dot org 2005-12-13 00:23 > --- > I am going to say this is 4.1 regression as it worked in 4.0.0 when removing > the -fno-tree-copy-prop option but fails on the mainline and 4.1 branche with > it. Somehow or another someone could come up with a testcase which fails also > without any options which turn off optimizations (it is just harder to come up > with one). I've checked in the same fix from the 4.1 branch into the mainline sources. I haven't found a way to trip the bug in the mainline, but the code is clearly wrong by inspection, so I went ahead and fixed it. Jeff -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23838
[Bug tree-optimization/23838] [4.1/4.2 Regression] infinite loop in dse
--- Comment #6 from law at redhat dot com 2005-12-16 07:06 --- Fixed by included patch. -- law at redhat dot com changed: What|Removed |Added Status|NEW |RESOLVED Resolution||FIXED http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23838
