am 3dd51ae3: am 2d4629c5: Merge branch \'upstream\' into merge_2013_03_18

am 3dd51ae3: am 2d4629c5: Merge branch \'upstream\' into merge_2013_03_18

* commit '3dd51ae3a043f2edf9dd2bc7c906c3f602967e5a': (424 commits)
  Change NULL to 0.
  Register the flush function for each compile unit.
  Remove trailing spaces.
  Fix PPC unaligned 64-bit loads and stores
  ARM cost model: Make some vector integer to float casts cheaper
  ARM cost model: Correct cost for some cheap float to integer conversions
  Extend global merge pass to optionally consider global constant variables. Also add some checks to not merge globals used within landing pad instructions or marked as "used".
  Change test cases to handle unaligned references.
  Remove unnecessary leading comment characters in lit-only file
  Add SchedRW annotations to most of X86InstrSSE.td.
  Annotate X86 arithmetic instructions with SchedRW lists.
  Check whether a pointer is non-null (isKnownNonNull) in isKnownNonZero.
  TableGen fix for the new machine model.
  Include '.test' suffix in target specific lit configs that need it
  Make the fields in the diagram match the descriptive text above them.
  Update
  Fix 80-col. violations in PPCCTRLoops
  Fix large count and negative constant count handling in PPCCTRLoops
  Cleanup initial-value constants in PPCCTRLoops
  Fix integer comparison in DIEInteger::BestForm.
  ...