[llvm] [Vectorize] Simplify code with DenseMap::operator[] (NFC) (PR #115635)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/115635.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp (+4-4) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp b/llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp
index dd005682203b75..f653269713b30b 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp
@@ -297,12 +297,12 @@ void UnrollState::unrollRecipeByUF(VPRecipeBase &R) {
     if (auto *Red = dyn_cast<VPReductionRecipe>(&R)) {
       auto *Phi = cast<VPReductionPHIRecipe>(R.getOperand(0));
       if (Phi->isOrdered()) {
-        auto Ins = VPV2Parts.insert({Phi, {}});
+        auto &Parts = VPV2Parts[Phi];
         if (Part == 1) {
-          Ins.first->second.clear();
-          Ins.first->second.push_back(Red);
+          Parts.clear();
+          Parts.push_back(Red);
         }
-        Ins.first->second.push_back(Copy->getVPSingleValue());
+        Parts.push_back(Copy->getVPSingleValue());
         Phi->setOperand(1, Copy->getVPSingleValue());
       }
     }

``````````

</details>


https://github.com/llvm/llvm-project/pull/115635