[BasicAA] Remove unused variables (NFC)

Split out from #98608.

Author: nikic

llvm/lib/Analysis/BasicAliasAnalysis.cpp

@@ -1159,8 +1159,6 @@ AliasResult BasicAAResult::aliasGEP(
     APInt &Off = DecompGEP1.Offset;
 
     // Initialize for Off >= 0 (V2 <= GEP1) case.
-    const Value *LeftPtr = V2;
-    const Value *RightPtr = GEP1;
     LocationSize VLeftSize = V2Size;
     LocationSize VRightSize = V1Size;
     const bool Swapped = Off.isNegative();
@@ -1172,7 +1170,6 @@ AliasResult BasicAAResult::aliasGEP(
       // ---------------->|
       // |-->V1Size       |-------> V2Size
       // GEP1             V2
-      std::swap(LeftPtr, RightPtr);
       std::swap(VLeftSize, VRightSize);
       Off = -Off;
     }