[PATCH] D119148: [LoopUnroll] Always respect user unroll pragma

[Whitney Tsang via Phabricator via llvm-commits]

Whitney created this revision.
Whitney added a reviewer: Meinersbur.
Whitney added a project: LoopOptWG.
Herald added subscribers: zzheng, hiraditya.
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Herald added a project: LLVM.
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IMO when user provide unroll pragma, compiler should always respect it.
It is not clear to me why loop unroll pass currently ensure that the unrolled loop size is limited by `PragmaUnrollThreshold`.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D119148

Files:
  llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp


Index: llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -788,14 +788,12 @@
 
   // 2nd priority is unroll count set by pragma.
   if (PInfo.PragmaCount > 0) {
-    if ((UP.AllowRemainder || (TripMultiple % PInfo.PragmaCount == 0)) &&
-        UCE.getUnrolledLoopSize(UP, PInfo.PragmaCount) < PragmaUnrollThreshold)
+    if ((UP.AllowRemainder || (TripMultiple % PInfo.PragmaCount == 0)))
       return PInfo.PragmaCount;
   }
 
   if (PInfo.PragmaFullUnroll && TripCount != 0) {
-    if (UCE.getUnrolledLoopSize(UP, TripCount) < PragmaUnrollThreshold)
-      return TripCount;
+    return TripCount;
   }
   // if didn't return until here, should continue to other priorties
   return None;


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