[PATCH] D48048: [LV] Prevent LV to run cost model twice for VF=2

[Ayal Zaks via Phabricator via llvm-commits]

Ayal added inline comments.


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Comment at: lib/Transforms/Vectorize/LoopVectorize.cpp:5033
 
   for (unsigned i = 2; i <= MaxVF; i *= 2) {
     // Notice that the vector loop needs to be executed less times, so
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Could have alternatively started from `unsigned i = 2 * Width`, as the condition above is essentially peeling the first iteration.

Ideally computing `expectedCost(1)` would also be saved in this case.


Repository:
  rL LLVM

https://reviews.llvm.org/D48048