[VPlan] Improve style around container-inserts (NFC)

Author: artagnon

llvm/lib/Transforms/Vectorize/VPlan.cpp

@@ -1473,15 +1473,15 @@ void VPSlotTracker::assignName(const VPValue *V) {
   std::string BaseName = (Twine(Prefix) + Name + Twine(">")).str();
 
   // First assign the base name for V.
-  const auto &[A, _] = VPValue2Name.insert({V, BaseName});
+  const auto &[A, _] = VPValue2Name.try_emplace(V, BaseName);
   // Integer or FP constants with different types will result in he same string
   // due to stripping types.
   if (V->isLiveIn() && isa<ConstantInt, ConstantFP>(UV))
     return;
 
   // If it is already used by C > 0 other VPValues, increase the version counter
   // C and use it for V.
-  const auto &[C, UseInserted] = BaseName2Version.insert({BaseName, 0});
+  const auto &[C, UseInserted] = BaseName2Version.try_emplace(BaseName, 0);
   if (!UseInserted) {
     C->second++;
     A->second = (BaseName + Twine(".") + Twine(C->second)).str();

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

@@ -142,7 +142,7 @@ static bool sinkScalarOperands(VPlan &Plan) {
       for (VPValue *Op : Recipe.operands())
         if (auto *Def =
                 dyn_cast_or_null<VPSingleDefRecipe>(Op->getDefiningRecipe()))
-          WorkList.insert(std::make_pair(VPBB, Def));
+          WorkList.insert({VPBB, Def});
     }
   }
 
@@ -206,7 +206,7 @@ static bool sinkScalarOperands(VPlan &Plan) {
     for (VPValue *Op : SinkCandidate->operands())
       if (auto *Def =
               dyn_cast_or_null<VPSingleDefRecipe>(Op->getDefiningRecipe()))
-        WorkList.insert(std::make_pair(SinkTo, Def));
+        WorkList.insert({SinkTo, Def});
     Changed = true;
   }
   return Changed;
@@ -910,10 +910,10 @@ static void removeRedundantExpandSCEVRecipes(VPlan &Plan) {
     if (!ExpR)
       continue;
 
-    auto I = SCEV2VPV.insert({ExpR->getSCEV(), ExpR});
-    if (I.second)
+    const auto &[V, Inserted] = SCEV2VPV.try_emplace(ExpR->getSCEV(), ExpR);
+    if (Inserted)
       continue;
-    ExpR->replaceAllUsesWith(I.first->second);
+    ExpR->replaceAllUsesWith(V->second);
     ExpR->eraseFromParent();
   }
 }

llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp

@@ -92,18 +92,19 @@ class UnrollState {
   void addRecipeForPart(VPRecipeBase *OrigR, VPRecipeBase *CopyR,
                         unsigned Part) {
     for (const auto &[Idx, VPV] : enumerate(OrigR->definedValues())) {
-      auto Ins = VPV2Parts.insert({VPV, {}});
-      assert(Ins.first->second.size() == Part - 1 && "earlier parts not set");
-      Ins.first->second.push_back(CopyR->getVPValue(Idx));
+      const auto &[V, _] = VPV2Parts.try_emplace(VPV, SmallVector<VPValue *>());
+      assert(V->second.size() == Part - 1 && "earlier parts not set");
+      V->second.push_back(CopyR->getVPValue(Idx));
     }
   }
 
   /// Given a uniform recipe \p R, add it for all parts.
   void addUniformForAllParts(VPSingleDefRecipe *R) {
-    auto Ins = VPV2Parts.insert({R, {}});
-    assert(Ins.second && "uniform value already added");
+    const auto &[V, Inserted] =
+        VPV2Parts.try_emplace(R, SmallVector<VPValue *>());
+    assert(Inserted && "uniform value already added");
     for (unsigned Part = 0; Part != UF; ++Part)
-      Ins.first->second.push_back(R);
+      V->second.push_back(R);
   }
 
   bool contains(VPValue *VPV) const { return VPV2Parts.contains(VPV); }