[PATCH] D90418: [debuginfo] Vectorizing a loop doesn't terminate all vectorized variable locations

[Chris Jackson via Phabricator via llvm-commits]

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This is an initial fix for BZ39018 <https://bugs.llvm.org/show_bug.cgi?id=39018>. The source file loop induction variable and its debug users and set to undef to prevent misleading values being presented. This is the simple 'don't mislead the user' fix, but there are possible improvements.

I intend to expand this work so that rather than permanently setting the original induction variable to 'undef', its value will reflect the the value for the vectorzied loops. For example, if a single iteration of the vectorized loop has width 4, compared to the previous 1, then the induction variable should increase in value by '4' per iteration.

There is some additional complexity as the vectorizer may use vector instructions of varying width to 'fit' the maximum iterations defined in the original source.


https://reviews.llvm.org/D90418

Files:
  llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
  llvm/test/DebugInfo/pr39018.ll

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