[llvm] [IVDesc] Make getCastInsts return an ArrayRef (NFC) (PR #169021)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Ramkumar Ramachandra (artagnon)

<details>
<summary>Changes</summary>

To make it clear that the return value is immutable.

---
Full diff: https://github.com/llvm/llvm-project/pull/169021.diff


4 Files Affected:

- (modified) llvm/include/llvm/Analysis/IVDescriptors.h (+1-3) 
- (modified) llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp (+1-1) 
- (modified) llvm/lib/Transforms/Vectorize/LoopVectorize.cpp (+1-2) 
- (modified) llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp (+1-1) 


``````````diff
diff --git a/llvm/include/llvm/Analysis/IVDescriptors.h b/llvm/include/llvm/Analysis/IVDescriptors.h
index 654a5f10cea96..724ab8364249d 100644
--- a/llvm/include/llvm/Analysis/IVDescriptors.h
+++ b/llvm/include/llvm/Analysis/IVDescriptors.h
@@ -454,9 +454,7 @@ class InductionDescriptor {
   /// Returns a reference to the type cast instructions in the induction
   /// update chain, that are redundant when guarded with a runtime
   /// SCEV overflow check.
-  const SmallVectorImpl<Instruction *> &getCastInsts() const {
-    return RedundantCasts;
-  }
+  ArrayRef<Instruction *> getCastInsts() const { return RedundantCasts; }
 
 private:
   /// Private constructor - used by \c isInductionPHI.
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp
index 86e742ca5fec1..ba21bbbe112e6 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp
@@ -684,7 +684,7 @@ void LoopVectorizationLegality::addInductionPhi(
   // in the vectorized loop body, record them here. All casts could be recorded
   // here for ignoring, but suffices to record only the first (as it is the
   // only one that may bw used outside the cast sequence).
-  const SmallVectorImpl<Instruction *> &Casts = ID.getCastInsts();
+  ArrayRef<Instruction *> Casts = ID.getCastInsts();
   if (!Casts.empty())
     InductionCastsToIgnore.insert(*Casts.begin());
 
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 5b8725178521e..5ae90aa76c27d 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -6575,8 +6575,7 @@ void LoopVectorizationCostModel::collectValuesToIgnore() {
   // detection.
   for (const auto &Induction : Legal->getInductionVars()) {
     const InductionDescriptor &IndDes = Induction.second;
-    const SmallVectorImpl<Instruction *> &Casts = IndDes.getCastInsts();
-    VecValuesToIgnore.insert_range(Casts);
+    VecValuesToIgnore.insert_range(IndDes.getCastInsts());
   }
 }
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index a6a03c0d805fd..6cffdcce4013d 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -512,7 +512,7 @@ static void removeRedundantInductionCasts(VPlan &Plan) {
     // replace it with the original IV. Note that only the final cast is
     // expected to have users outside the cast-chain and the dead casts left
     // over will be cleaned up later.
-    auto &Casts = IV->getInductionDescriptor().getCastInsts();
+    ArrayRef<Instruction *> Casts = IV->getInductionDescriptor().getCastInsts();
     VPValue *FindMyCast = IV;
     for (Instruction *IRCast : reverse(Casts)) {
       VPSingleDefRecipe *FoundUserCast = nullptr;

``````````

</details>


https://github.com/llvm/llvm-project/pull/169021