Opened 11 years ago

Last modified 11 years ago

#11227 closed defect

gcc-4.6.0 optimization bug with cliquer-1.2.p7.spkg — at Version 6

Reported by: mariah Owned by: mariah
Priority: blocker Milestone: sage-4.7
Component: packages: standard Keywords: cliquer spkg
Cc: Merged in:
Authors: Reviewers:
Report Upstream: Fixed upstream, but not in a stable release. Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Status badges

Description (last modified by jdemeyer)

On various 64-bit x86_64 Linux machines (for example, the Skynet machine eno), sage-4.7.alpha5 built with gcc-4.6.0 fails various tests with a timeout:

sage -t -long  -force_lib devel/sage/sage/graphs/graph_generators.py # Time out
sage -t -long  -force_lib devel/sage/sage/graphs/graph_coloring.py # Time out
sage -t -long  -force_lib devel/sage/sage/graphs/graph.py # Time out
sage -t -long  -force_lib devel/sage/sage/graphs/cliquer.pyx # Time out

The problem can be seen by executing the following command, which should take milliseconds but simply hangs instead:

sage: clique_number(Graph({0:[1,2,3], 1:[2], 3:[0,1]}))

For other gcc 4.6.0 specific problems see #11216.

Change History (6)

comment:1 Changed 11 years ago by mariah

  • Milestone set to sage-4.7.1
  • Owner changed from tbd to mariah

The following code triggers the problem (code does not return):

sage: g = graphs.BidiakisCube();
sage: g.clique_number()

If cliquer-1.2.p7.spkg is rebuilt with -O1 rather than -O2, then the problem goes away.

comment:2 Changed 11 years ago by mariah

If src/reorder.c is built with -O1 rather than -O2, then the problem goes away.

comment:3 follow-up: Changed 11 years ago by drkirkby

  • Description modified (diff)

On what platform is this problem?

Dave

comment:4 in reply to: ↑ 3 Changed 11 years ago by mariah

Replying to drkirkby:

On what platform is this problem?

Dave

Apologies for not mentioning this. I see the problem on skynet:eno (x86_64-Linux-core2). I have not checked to see if the problem exists on other architectures.

comment:5 Changed 11 years ago by jdemeyer

  • Description modified (diff)
  • Keywords cliquer added

comment:6 Changed 11 years ago by jdemeyer

  • Description modified (diff)
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