[llvm] Delete pointers without null checks (NFC) (#168183)

Identified with readability-delete-null-pointer.

Author: kazutakahirata

llvm/include/llvm/ADT/ConcurrentHashtable.h

@@ -342,10 +342,8 @@ class ConcurrentHashTableByPtr {
     CurBucket.Size = NewBucketSize;
 
     // Delete old bucket entries.
-    if (SrcHashes != nullptr)
-      delete[] SrcHashes;
-    if (SrcEntries != nullptr)
-      delete[] SrcEntries;
+    delete[] SrcHashes;
+    delete[] SrcEntries;
   }
 
   uint32_t getBucketIdx(hash_code Hash) { return Hash & HashMask; }

llvm/lib/Target/Hexagon/HexagonHazardRecognizer.h

@@ -50,10 +50,7 @@ class HexagonHazardRecognizer : public ScheduleHazardRecognizer {
                           const HexagonSubtarget &ST)
     : Resources(ST.createDFAPacketizer(II)), TII(HII) { }
 
-  ~HexagonHazardRecognizer() override {
-    if (Resources)
-      delete Resources;
-  }
+  ~HexagonHazardRecognizer() override { delete Resources; }
 
   /// This callback is invoked when a new block of instructions is about to be
   /// scheduled. The hazard state is set to an initialized state.

llvm/lib/Transforms/Vectorize/VPlan.cpp

@@ -884,8 +884,7 @@ VPlan::~VPlan() {
   }
   for (VPValue *VPV : getLiveIns())
     delete VPV;
-  if (BackedgeTakenCount)
-    delete BackedgeTakenCount;
+  delete BackedgeTakenCount;
 }
 
 VPIRBasicBlock *VPlan::getExitBlock(BasicBlock *IRBB) const {