[mlir][OpenMP] Fix memory leak by deleting unused value

Reviewed By: ftynse, rriddle

Differential Revision: https://reviews.llvm.org/D122633

Author: shraiysh

mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp

@@ -1219,14 +1219,13 @@ convertOmpAtomicCapture(omp::AtomicCaptureOp atomicCaptureOp,
   };
   // Handle ambiguous alloca, if any.
   auto allocaIP = findAllocaInsertPoint(builder, moduleTranslation);
-  llvm::UnreachableInst *unreachableInst;
   if (allocaIP.getPoint() == ompLoc.IP.getPoint()) {
     // Same point => split basic block and make them unambigous.
-    unreachableInst = builder.CreateUnreachable();
+    llvm::UnreachableInst *unreachableInst = builder.CreateUnreachable();
     builder.SetInsertPoint(builder.GetInsertBlock()->splitBasicBlock(
         unreachableInst, "alloca_split"));
     ompLoc.IP = builder.saveIP();
-    unreachableInst->removeFromParent();
+    unreachableInst->eraseFromParent();
   }
   builder.restoreIP(ompBuilder->createAtomicCapture(
       ompLoc, findAllocaInsertPoint(builder, moduleTranslation), llvmAtomicX,