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  1. Mar 27, 2012
  2. Mar 26, 2012
  3. Mar 25, 2012
    • Chandler Carruth's avatar
      Teach instsimplify how to simplify comparisons of pointers which are · 8059c84a
      Chandler Carruth authored
      constant-offsets of a common base using the generic GEP-walking logic
      I added for computing pointer differences in the same situation.
      
      llvm-svn: 153419
      8059c84a
    • Chandler Carruth's avatar
      Switch the pointer-difference simplification logic to only work with · 2741aae8
      Chandler Carruth authored
      inbounds GEPs. This isn't really necessary for simplifying pointer
      differences, but I'm planning to re-use the same code to simplify
      pointer comparisons where it is necessary. Since real code almost
      exclusively uses inbounds GEPs, it doesn't seem worth it to support the
      extra complexity of turning it on and off. If anyone would like that
      back, feel free to shout. Note that instcombine will still catch any of
      these patterns.
      
      llvm-svn: 153418
      2741aae8
    • Craig Topper's avatar
      Prune some includes and forward declarations. · d4a964cd
      Craig Topper authored
      llvm-svn: 153415
      d4a964cd
    • Chandler Carruth's avatar
      Teach the function cloner (and thus the inliner) to simplify PHINodes · ef82cf5b
      Chandler Carruth authored
      aggressively. There are lots of dire warnings about this being expensive
      that seem to predate switching to the TrackingVH-based value remapper
      that is automatically updated on RAUW. This makes it easy to not just
      prune single-entry PHIs, but to fully simplify PHIs, and to recursively
      simplify the newly inlined code to propagate PHINode simplifications.
      
      This introduces a bit of a thorny problem though. We may end up
      simplifying a branch condition to a constant when we fold PHINodes, and
      we would like to nuke any dead blocks resulting from this so that time
      isn't wasted continually analyzing them, but this isn't easy. Deleting
      basic blocks *after* they are fully cloned and mapped into the new
      function currently requires manually updating the value map. The last
      piece of the simplification-during-inlining puzzle will require either
      switching to WeakVH mappings or some other piece of refactoring. I've
      left a FIXME in the testcase about this.
      
      llvm-svn: 153410
      ef82cf5b
    • Chandler Carruth's avatar
      Move the instruction simplification of callsite arguments in the inliner · 21211992
      Chandler Carruth authored
      to instead rely on much more generic and powerful instruction
      simplification in the function cloner (and thus inliner).
      
      This teaches the pruning function cloner to use instsimplify rather than
      just the constant folder to fold values during cloning. This can
      simplify a large number of things that constant folding alone cannot
      begin to touch. For example, it will realize that 'or' and 'and'
      instructions with certain constant operands actually become constants
      regardless of what their other operand is. It also can thread back
      through the caller to perform simplifications that are only possible by
      looking up a few levels. In particular, GEPs and pointer testing tend to
      fold much more heavily with this change.
      
      This should (in some cases) have a positive impact on compile times with
      optimizations on because the inliner itself will simply avoid cloning
      a great deal of code. It already attempted to prune proven-dead code,
      but now it will be use the stronger simplifications to prove more code
      dead.
      
      llvm-svn: 153403
      21211992
    • Chandler Carruth's avatar
      Add an asserting ValueHandle to the block simplification code which will · 0c72e3f4
      Chandler Carruth authored
      fire if anything ever invalidates the assumption of a terminator
      instruction being unchanged throughout the routine.
      
      I've convinced myself that the current definition of simplification
      precludes such a transformation, so I think getting some asserts
      coverage that we don't violate this agreement is sufficient to make this
      code safe for the foreseeable future.
      
      Comments to the contrary or other suggestions are of course welcome. =]
      The bots are now happy with this code though, so it appears the bug here
      has indeed been fixed.
      
      llvm-svn: 153401
      0c72e3f4
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