Silviu Baranga d8cc816f81 Re-commit [SCEV] Introduce a guarded backedge taken count and use it in LAA and LV ... This re-commits r265535 which was reverted in r265541 because it broke the windows bots. The problem was that we had a PointerIntPair which took a pointer to a struct allocated with new. The problem was that new doesn't provide sufficient alignment guarantees. This pattern was already present before r265535 and it just happened to work. To fix this, we now separate the PointerToIntPair from the ExitNotTakenInfo struct into a pointer and a bool. Original commit message: Summary: When the backedge taken codition is computed from an icmp, SCEV can deduce the backedge taken count only if one of the sides of the icmp is an AddRecExpr. However, due to sign/zero extensions, we sometimes end up with something that is not an AddRecExpr. However, we can use SCEV predicates to produce a 'guarded' expression. This change adds a method to SCEV to get this expression, and the SCEV predicate associated with it. In HowManyGreaterThans and HowManyLessThans we will now add a SCEV predicate associated with the guarded backedge taken count when the analyzed SCEV expression is not an AddRecExpr. Note that we only do this as an alternative to returning a 'CouldNotCompute'. We use new feature in Loop Access Analysis and LoopVectorize to analyze and transform more loops. Reviewers: anemet, mzolotukhin, hfinkel, sanjoy Subscribers: flyingforyou, mcrosier, atrick, mssimpso, sanjoy, mzolotukhin, llvm-commits Differential Revision: http://reviews.llvm.org/D17201 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265786 91177308-0d34-0410-b5e6-96231b3b80d8		2016-04-08 14:29:09 +00:00
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llvm	Re-commit [SCEV] Introduce a guarded backedge taken count and use it in LAA and LV	2016-04-08 14:29:09 +00:00
llvm-c	[llvm-c] Expose LLVMContextGetDiagnostic{Handler,Context}	2016-04-08 09:19:02 +00:00