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c7b8b5e22d
Summary: The main goal is to able to start using the new OptRemarkEmitter analysis from the LoopVectorizer. Since the vectorizer was recently converted to the new PM, it makes sense to convert this analysis as well. This pass is currently tested through the LoopDistribution pass, so I am also porting LoopDistribution to get coverage for this analysis with the new PM. Reviewers: davidxl, silvas Subscribers: llvm-commits, mzolotukhin Differential Revision: https://reviews.llvm.org/D22436 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275810 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))
//===---------------------------------------------------------------------===//