• Graphite_Phone_Call
• 2009_07_22

Attendees: Razya, Antonio, David, Ramakrishna, Sebastian, Li, Konrad, Michael, Tobias

Recorded phone call

• Reductions (Sebastian)
  • fold-const.i miscompiles just with SCoP detection.
  • Almost every benchmark passes, but problems with dependency checks
    • (memory usage)
  • 3 test cases still fail
• Dependency check (Konrad)
  • Remove caching of dependency polyhedron
  • cray_pointers2 runtime to long. (380000 polyhedrons)
• Alias analysis (Li, Konrad, Tobi)
  • NP hard
  • another structure
  • Representation as polyhedron but conservative
  • Heuristics
  • call in gimple alias oracle
• CLooG
• Michael (joined us)

  • LooPo

  • Adapting LooPo to Graphite

  • Data dependency algorithms. Usign
• Vectorizer / Casting Problem (Ramakrishna)
  • 2007 bugreport
  • not just signed/unsigned but general type problem
  • (Modulo semantics)
    • number of iterations improvements using PPL (Sebastian)
• Integer polytopes
  • Problem of testing for emptyness
  • Plans to implement PIP in PPL (by INRIA)
  • Current problem in PPL is that it finds to minimize the integral polyhedron,
    • but rational points are allowed to.
• Merge
  • Autopar patch of Razya

  • ScalarEvolution patch (Sebastian)

  • Reductions patch
  • Blocking blocked by interchange heuristics
• Strip mining
  • We do no atomic strip mining of the loop
  • Atomic strip mining has to be made