Silviu Baranga d19d7b747a Re-commit r255115, with the PredicatedScalarEvolution class moved to ... ScalarEvolution.h, in order to avoid cyclic dependencies between the Transform and Analysis modules: [LV][LAA] Add a layer over SCEV to apply run-time checked knowledge on SCEV expressions Summary: This change creates a layer over ScalarEvolution for LAA and LV, and centralizes the usage of SCEV predicates. The SCEVPredicatedLayer takes the statically deduced knowledge by ScalarEvolution and applies the knowledge from the SCEV predicates. The end goal is that both LAA and LV should use this interface everywhere. This also solves a problem involving the result of SCEV expression rewritting when the predicate changes. Suppose we have the expression (sext {a,+,b}) and two predicates P1: {a,+,b} has nsw P2: b = 1. Applying P1 and then P2 gives us {a,+,1}, while applying P2 and the P1 gives us sext({a,+,1}) (the AddRec expression was changed by P2 so P1 no longer applies). The SCEVPredicatedLayer maintains the order of transformations by feeding back the results of previous transformations into new transformations, and therefore avoiding this issue. The SCEVPredicatedLayer maintains a cache to remember the results of previous SCEV rewritting results. This also has the benefit of reducing the overall number of expression rewrites. Reviewers: mzolotukhin, anemet Subscribers: jmolloy, sanjoy, llvm-commits Differential Revision: http://reviews.llvm.org/D14296 llvm-svn: 255122		2015-12-09 16:06:28 +00:00
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llvm	Re-commit r255115, with the PredicatedScalarEvolution class moved to	2015-12-09 16:06:28 +00:00
llvm-c	[IR] Add support for empty tokens	2015-11-11 21:57:16 +00:00