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  1. Nov 23, 2011
    • Jakob Stoklund Olesen's avatar
      Fix PR11422. · 02845410
      Jakob Stoklund Olesen authored
      This was a bug in keeping track of the available domains when merging
      domain values.
      
      The wrong domain mask caused ExecutionDepsFix to try to move VANDPSYrr
      to the integer domain which is only available in AVX2.
      
      Also add an assertion to catch future attempts at emitting AVX2
      instructions.
      
      llvm-svn: 145096
      02845410
    • Chandler Carruth's avatar
      Fix a crash in block placement due to an inner loop that happened to be · 4a87aa0c
      Chandler Carruth authored
      reversed in the function's original ordering, and we happened to
      encounter it while handling an outer unnatural CFG structure.
      
      Thanks to the test case reduced from GCC's source by Benjamin Kramer.
      This may also fix a crasher in gzip that Duncan reduced for me, but
      I haven't yet gotten to testing that one.
      
      llvm-svn: 145094
      4a87aa0c
  2. Nov 22, 2011
    • Chandler Carruth's avatar
      Fix a devilish miscompile exposed by block placement. The · ee54feb6
      Chandler Carruth authored
      updateTerminator code didn't correctly handle EH terminators in one very
      specific case. AnalyzeBranch would find no terminator instruction, and
      so the fallback in updateTerminator is to assume fallthrough. This is
      correct, but the destination of the fallthrough was assumed to be the
      first successor.
      
      This is *almost always* true, but in certain cases the loop
      transformations will cause the landing pad to be the first successor!
      Instead of this brittle logic, actually look through the successors for
      a non-landing-pad accessor, and to assert if more than one is found.
      
      This will hopefully fix some (if not all) of the self host miscompiles
      with block placement. Thanks to Benjamin Kramer for reporting, Nick
      Lewycky for an initial stab at a reduction, and Duncan for endless
      advice on EH (which I know nothing about) as well as reviewing the
      actual fix.
      
      llvm-svn: 145062
      ee54feb6
    • Chandler Carruth's avatar
      Fix an obvious omission in the SelectionDAGBuilder where we were · e2530dc8
      Chandler Carruth authored
      dropping weights on the floor for invokes. This was impeding my writing
      further test cases for invoke when interacting with probabilities and
      block placement.
      
      No test case as there doesn't appear to be a way to test this stuff. =/
      Suggestions for a test case of course welcome. I hope to be able to add
      test cases that indirectly cover this eventually by adding probabilities
      to the exceptional edge and reordering blocks as a result.
      
      llvm-svn: 145060
      e2530dc8
    • Rafael Espindola's avatar
      If a register is both an early clobber and part of a tied use, handle the use · 2021f382
      Rafael Espindola authored
      before the clobber so that we copy the value if needed.
      
      Fixes pr11415.
      
      llvm-svn: 145056
      2021f382
  3. Nov 20, 2011
    • Chandler Carruth's avatar
      The logic for breaking the CFG in the presence of hot successors didn't · 18dfac38
      Chandler Carruth authored
      properly account for the *global* probability of the edge being taken.
      This manifested as a very large number of unconditional branches to
      blocks being merged against the CFG even though they weren't
      particularly hot within the CFG.
      
      The fix is to check whether the edge being merged is both locally hot
      relative to other successors for the source block, and globally hot
      compared to other (unmerged) predecessors of the destination block.
      
      This introduces a new crasher on GCC single-source, but it's currently
      behind a flag, and Ben has offered to work on the reduction. =]
      
      llvm-svn: 145010
      18dfac38
  4. Nov 19, 2011
    • Chandler Carruth's avatar
      Move the handling of unanalyzable branches out of the loop-driven chain · f3dc9eff
      Chandler Carruth authored
      formation phase and into the initial walk of the basic blocks. We
      essentially pre-merge all blocks where unanalyzable fallthrough exists,
      as we won't be able to update the terminators effectively after any
      reorderings. This is quite a bit more principled as there may be CFGs
      where the second half of the unanalyzable pair has some analyzable
      predecessor that gets placed first. Then it may get placed next,
      implicitly breaking the unanalyzable branch even though we never even
      looked at the part that isn't analyzable. I've included a test case that
      triggers this (thanks Benjamin yet again!), and I'm hoping to synthesize
      some more general ones as I dig into related issues.
      
      Also, to make this new scheme work we have to be able to handle branches
      into the middle of a chain, so add this check. We always fallback on the
      incoming ordering.
      
      Finally, this starts to really underscore a known limitation of the
      current implementation -- we don't consider broken predecessors when
      merging successors. This can caused major missed opportunities, and is
      something I'm planning on looking at next (modulo more bug reports).
      
      llvm-svn: 144994
      f3dc9eff
  5. Nov 18, 2011
  6. Nov 17, 2011
    • Chad Rosier's avatar
      When fast iseling a GEP, accumulate the offset rather than emitting a series of · f83ab704
      Chad Rosier authored
      ADDs.  MaxOffs is used as a threshold to limit the size of the offset. Tradeoffs
      being: (1) If we can't materialize the large constant then we'll cause fast-isel
      to bail. (2) Too large of an offset can't be directly encoded in the ADD
      resulting in a MOV+ADD.  Generally not a bad thing because otherwise we would
      have had ADD+ADD, but on Thumb this turns into a MOVS+MOVT+ADD. Working on a fix
      for that. (3) Conversely, too low of a threshold we'll miss opportunities to 
      coalesce ADDs.
      rdar://10412592
      
      llvm-svn: 144886
      f83ab704
    • Eli Friedman's avatar
      Make sure to replace the chain properly when DAGCombining a... · ff1eaa75
      Eli Friedman authored
      Make sure to replace the chain properly when DAGCombining a LOAD+EXTRACT_VECTOR_ELT into a single LOAD.  Fixes PR10747/PR11393.
      
      llvm-svn: 144863
      ff1eaa75
  7. Nov 16, 2011
  8. Nov 15, 2011
  9. Nov 14, 2011
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