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2000a7c9b2
Other than moving code and adding the boilerplate for the new files, the code being moved is unchanged. There are a few global functions that are shared with the rest of the LoopVectorizer. I moved these to the new module as well (emitLoopAnalysis, stripIntegerCast, replaceSymbolicStrideSCEV) along with the Report class used by emitLoopAnalysis. There is probably room for further improvement in this area. I kept DEBUG_TYPE "loop-vectorize" because it's used as the PassName with emitOptimizationRemarkAnalysis. This will obviously have to change. NFC. This is part of the patchset that splits out the memory dependence logic from LoopVectorizationLegality into a new class LoopAccessAnalysis. LoopAccessAnalysis will be used by the new Loop Distribution pass. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227756 91177308-0d34-0410-b5e6-96231b3b80d8
Analysis Opportunities:
//===---------------------------------------------------------------------===//
In test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll, the
ScalarEvolution expression for %r is this:
{1,+,3,+,2}<loop>
Outside the loop, this could be evaluated simply as (%n * %n), however
ScalarEvolution currently evaluates it as
(-2 + (2 * (trunc i65 (((zext i64 (-2 + %n) to i65) * (zext i64 (-1 + %n) to i65)) /u 2) to i64)) + (3 * %n))
In addition to being much more complicated, it involves i65 arithmetic,
which is very inefficient when expanded into code.
//===---------------------------------------------------------------------===//
In formatValue in test/CodeGen/X86/lsr-delayed-fold.ll,
ScalarEvolution is forming this expression:
((trunc i64 (-1 * %arg5) to i32) + (trunc i64 %arg5 to i32) + (-1 * (trunc i64 undef to i32)))
This could be folded to
(-1 * (trunc i64 undef to i32))
//===---------------------------------------------------------------------===//