forked from OSchip/llvm-project
19 lines
669 B
Plaintext
19 lines
669 B
Plaintext
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Analysis Opportunities:
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//===---------------------------------------------------------------------===//
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In test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll, the
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ScalarEvolution expression for %r is this:
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{1,+,3,+,2}<loop>
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Outside the loop, this could be evaluated simply as (%n * %n), however
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ScalarEvolution currently evaluates it as
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(-2 + (2 * (trunc i65 (((zext i64 (-2 + %n) to i65) * (zext i64 (-1 + %n) to i65)) /u 2) to i64)) + (3 * %n))
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In addition to being much more complicated, it involves i65 arithmetic,
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which is very inefficient when expanded into code.
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//===---------------------------------------------------------------------===//
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