diff --git a/cryptlib.cpp b/cryptlib.cpp
index 9f1e749c..24eb0209 100644
--- a/cryptlib.cpp
+++ b/cryptlib.cpp
@@ -171,18 +171,18 @@ size_t BlockTransformation::AdvancedProcessBlocks(const byte *inBlocks, const by
 		outIncrement = 0-outIncrement;
 	}
 
-	// Coverity finding CID 147865. In practice, if BT_XorInput, then xorBlocks is non-NULL.
-	bool xorFlag = (flags & BT_XorInput) && (xorBlocks != NULLPTR);
 	while (length >= blockSize)
 	{
-		if (xorFlag)
+		if (flags & BT_XorInput)
 		{
+			// Coverity finding. However, xorBlocks is never NULL if BT_XorInput.
+			CRYPTOPP_ASSERT(xorBlocks);
 			xorbuf(outBlocks, xorBlocks, inBlocks, blockSize);
-			xorBlocks += xorIncrement;
 			ProcessBlock(outBlocks);
 		}
 		else
 		{
+			// xorBlocks can be NULL. See, for example, ECB_OneWay::ProcessData.
 			ProcessAndXorBlock(inBlocks, xorBlocks, outBlocks);
 		}
 
@@ -190,6 +190,7 @@ size_t BlockTransformation::AdvancedProcessBlocks(const byte *inBlocks, const by
 			const_cast<byte *>(inBlocks)[blockSize-1]++;
 		inBlocks += inIncrement;
 		outBlocks += outIncrement;
+		xorBlocks += xorIncrement;
 		length -= blockSize;
 	}