[llvm] [LV] Removing option that is no longer needed after recent updates to loop interleaving algorithm (PR #82955)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Nilanjana Basu (nilanjana87)

<details>
<summary>Changes</summary>

Recent set of changes (Ref: https://github.com/llvm/llvm-project/pull/67725) in loop interleaving algorithm removed the loop trip count threshold for allowing interleaving. Therefore `interleave-small-loop-scalar-reduction` option is no longer useful.


---
Full diff: https://github.com/llvm/llvm-project/pull/82955.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/LoopVectorize.cpp (+1-8) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 373ea751d568ae..b7ae932677bbe3 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -315,12 +315,6 @@ static cl::opt<bool> EnableLoadStoreRuntimeInterleave(
     cl::desc(
         "Enable runtime interleaving until load/store ports are saturated"));
 
-/// Interleave small loops with scalar reductions.
-static cl::opt<bool> InterleaveSmallLoopScalarReduction(
-    "interleave-small-loop-scalar-reduction", cl::init(false), cl::Hidden,
-    cl::desc("Enable interleaving for loops with small iteration counts that "
-             "contain scalar reductions to expose ILP."));
-
 /// The number of stores in a loop that are allowed to need predication.
 static cl::opt<unsigned> NumberOfStoresToPredicate(
     "vectorize-num-stores-pred", cl::init(1), cl::Hidden,
@@ -5477,8 +5471,7 @@ LoopVectorizationCostModel::selectInterleaveCount(ElementCount VF,
 
     // If there are scalar reductions and TTI has enabled aggressive
     // interleaving for reductions, we will interleave to expose ILP.
-    if (InterleaveSmallLoopScalarReduction && VF.isScalar() &&
-        AggressivelyInterleaveReductions) {
+    if (VF.isScalar() && AggressivelyInterleaveReductions) {
       LLVM_DEBUG(dbgs() << "LV: Interleaving to expose ILP.\n");
       // Interleave no less than SmallIC but not as aggressive as the normal IC
       // to satisfy the rare situation when resources are too limited.

``````````

</details>


https://github.com/llvm/llvm-project/pull/82955