[PATCH] D27911: [LoopUnroll] Keep UP.Count when considering complete unroll

[Z. Zheng via Phabricator via llvm-commits]

zzheng created this revision.
zzheng added reviewers: evstupac, mzolotukhin, zinob.
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r286389 updates UP.Count unconditionally when considering complete unroll of loop with compile-time known TripCount.
This can overwrite UP.Count retrieved by getUnrollingPreferences().


Repository:
  rL LLVM

https://reviews.llvm.org/D27911

Files:
  lib/Transforms/Scalar/LoopUnrollPass.cpp


Index: lib/Transforms/Scalar/LoopUnrollPass.cpp
===================================================================
--- lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -782,7 +782,7 @@
   assert((ExactTripCount == 0 || MaxTripCount == 0) &&
          "ExtractTripCound and MaxTripCount cannot both be non zero.");
   unsigned FullUnrollTripCount = ExactTripCount ? ExactTripCount : MaxTripCount;
-  UP.Count = FullUnrollTripCount;
+  UP.Count = UP.Count ? UP.Count : FullUnrollTripCount;
   if (FullUnrollTripCount && FullUnrollTripCount <= UP.FullUnrollMaxCount) {
     // When computing the unrolled size, note that BEInsns are not replicated
     // like the rest of the loop body.


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