diff --git a/src/core/io/qiodevice.cpp b/src/core/io/qiodevice.cpp
index da43d29ec..154b7564d 100644
--- a/src/core/io/qiodevice.cpp
+++ b/src/core/io/qiodevice.cpp
@@ -78,7 +78,7 @@ void debugBinaryString(const QByteArray &input)
     printf("\n\n");
 }
 
-void debugBinaryString(const char *data, qint64 maxlen)
+inline void debugBinaryString(const char *data, qint64 maxlen)
 {
     debugBinaryString(QByteArray(data, maxlen));
 }
diff --git a/src/core/io/qiodevice_p.h b/src/core/io/qiodevice_p.h
index 1a4c181f3..643b0f8eb 100644
--- a/src/core/io/qiodevice_p.h
+++ b/src/core/io/qiodevice_p.h
@@ -86,7 +86,7 @@ public:
     bool isEmpty() const {
         return len == 0;
     }
-    void skip(int n) {
+    void skip(const int n) {
         if (n >= len) {
             clear();
         } else {
@@ -97,30 +97,30 @@ public:
     int getChar() {
         if (len == 0)
             return -1;
-        int ch = uchar(*first);
+        const int ch = uchar(*first);
         len--;
         first++;
         return ch;
     }
-    int read(char* target, int size) {
-        int r = qMin(size, len);
+    int read(char* target, const int size) {
+        const int r = qMin(size, len);
         memcpy(target, first, r);
         len -= r;
         first += r;
         return r;
     }
-    int peek(char* target, int size) {
-        int r = qMin(size, len);
+    int peek(char* target, const int size) {
+        const int r = qMin(size, len);
         memcpy(target, first, r);
         return r;
     }
-    char* reserve(int size) {
+    char* reserve(const int size) {
         makeSpace(size + len, freeSpaceAtEnd);
         char* writePtr = first + len;
         len += size;
         return writePtr;
     }
-    void chop(int size) {
+    void chop(const int size) {
         if (size >= len) {
             clear();
         } else {
@@ -129,7 +129,7 @@ public:
     }
     QByteArray readAll() {
         char* f = first;
-        int l = len;
+        const int l = len;
         clear();
         return QByteArray(f, l);
     }
@@ -171,7 +171,7 @@ private:
         size_t newCapacity = qMax(capacity, size_t(QIODEVICE_BUFFERSIZE));
         while (newCapacity < required)
             newCapacity *= 2;
-        int moveOffset = (where == freeSpaceAtEnd) ? 0 : newCapacity - len;
+        const int moveOffset = (where == freeSpaceAtEnd) ? 0 : newCapacity - len;
         if (newCapacity > capacity) {
             // allocate more space
             char* newBuf = new char[newCapacity];
@@ -186,7 +186,6 @@ private:
         first = buf + moveOffset;
     }
 
-private:
     // length of the unread data
     int len;
     // start of the unread data
@@ -197,7 +196,7 @@ private:
     size_t capacity;
 };
 
-class Q_CORE_EXPORT QIODevicePrivate
+class QIODevicePrivate
 #ifndef QT_NO_QOBJECT
     : public QObjectPrivate
 #endif
diff --git a/src/core/tools/qbitarray.cpp b/src/core/tools/qbitarray.cpp
index a0a3bd47f..c6161e8a6 100644
--- a/src/core/tools/qbitarray.cpp
+++ b/src/core/tools/qbitarray.cpp
@@ -154,37 +154,10 @@ QBitArray::QBitArray(int size, bool value)
 int QBitArray::count(bool on) const
 {
     int numBits = 0;
-    int len = size();
-#if 0
+    const int len = size();
     for (int i = 0; i < len; ++i)
         numBits += testBit(i);
-#else
-    // See http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel
-    const quint8 *bits = reinterpret_cast<const quint8 *>(d.data()) + 1;
-    while (len >= 32) {
-        quint32 v = quint32(bits[0]) | (quint32(bits[1]) << 8) | (quint32(bits[2]) << 16) | (quint32(bits[3]) << 24);
-        quint32 c = ((v & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f;
-        c += (((v & 0xfff000) >> 12) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f;
-        c += ((v >> 24) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f;
-        len -= 32;
-        bits += 4;
-        numBits += int(c);
-    }
-    while (len >= 24) {
-        quint32 v = quint32(bits[0]) | (quint32(bits[1]) << 8) | (quint32(bits[2]) << 16);
-        quint32 c =  ((v & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f;
-        c += (((v & 0xfff000) >> 12) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f;    
-        len -= 24;
-        bits += 3;
-        numBits += int(c);
-    }
-    while (len >= 0) {
-        if (bits[len / 8] & (1 << ((len - 1) & 7)))
-            ++numBits;
-        --len;
-    }
-#endif
-    return on ? numBits : size() - numBits;
+    return on ? numBits : len - numBits;
 }
 
 /*!
@@ -694,8 +667,8 @@ QDataStream &operator>>(QDataStream &in, QBitArray &ba)
     quint32 len;
     in >> len;
     if (len == 0) {
-	ba.clear();
-	return in;
+        ba.clear();
+        return in;
     }
 
     const quint32 Step = 8 * 1024 * 1024;
diff --git a/src/core/tools/qbytearray.cpp b/src/core/tools/qbytearray.cpp
index e99df40ac..f2d6aecc6 100644
--- a/src/core/tools/qbytearray.cpp
+++ b/src/core/tools/qbytearray.cpp
@@ -2183,7 +2183,7 @@ QList<QByteArray> QByteArray::split(char sep) const
         ba.repeated(4);             // returns "abababab"
     \endcode
 */
-QByteArray QByteArray::repeated(int times) const
+QByteArray QByteArray::repeated(const int times) const
 {
     if (d->size == 0)
         return *this;
@@ -2229,7 +2229,7 @@ QByteArray QByteArray::repeated(int times) const
     \sa lastIndexOf(), contains(), count()
 */
 
-int QByteArray::indexOf(const QByteArray &ba, int from) const
+int QByteArray::indexOf(const QByteArray &ba, const int from) const
 {
     const int ol = ba.d->size;
     if (ol == 0)
@@ -2271,7 +2271,7 @@ int QByteArray::indexOf(const QByteArray &ba, int from) const
     \a str in the byte array, searching forward from index position \a
     from. Returns -1 if \a str could not be found.
 */
-int QByteArray::indexOf(const char *c, int from) const
+int QByteArray::indexOf(const char *c, const int from) const
 {
     const int ol = qstrlen(c);
     if (ol == 1)
@@ -2575,7 +2575,7 @@ bool QByteArray::endsWith(const char *str) const
 {
     if (!str || !*str)
         return true;
-    int len = qstrlen(str);
+    const int len = qstrlen(str);
     if (d->size < len)
         return false;
     return qstrncmp(d->data + d->size - len, str, len) == 0;
@@ -2681,11 +2681,9 @@ QByteArray QByteArray::toLower() const
 {
     QByteArray s(*this);
     uchar *p = reinterpret_cast<uchar *>(s.data());
-    if (p) {
-        while (*p) {
-            *p = QChar::toLower((ushort)*p);
-            p++;
-        }
+    while (*p) {
+        *p = QChar::toLower((ushort)*p);
+        p++;
     }
     return s;
 }
@@ -2704,11 +2702,9 @@ QByteArray QByteArray::toUpper() const
 {
     QByteArray s(*this);
     uchar *p = reinterpret_cast<uchar *>(s.data());
-    if (p) {
-        while (*p) {
-            *p = QChar::toUpper((ushort)*p);
-            p++;
-        }
+    while (*p) {
+        *p = QChar::toUpper((ushort)*p);
+        p++;
     }
     return s;
 }
diff --git a/src/core/tools/qbytearray.h b/src/core/tools/qbytearray.h
index 766bd1773..61425a098 100644
--- a/src/core/tools/qbytearray.h
+++ b/src/core/tools/qbytearray.h
@@ -164,11 +164,11 @@ public:
     QByteRef operator[](uint i);
 
     int indexOf(char c, int from = 0) const;
-    int indexOf(const char *c, int from = 0) const;
-    int indexOf(const QByteArray &a, int from = 0) const;
-    int lastIndexOf(char c, int from = -1) const;
-    int lastIndexOf(const char *c, int from = -1) const;
-    int lastIndexOf(const QByteArray &a, int from = -1) const;
+    int indexOf(const char *c, const int from = 0) const;
+    int indexOf(const QByteArray &a, const int from = 0) const;
+    int lastIndexOf(char c, const int from = -1) const;
+    int lastIndexOf(const char *c, const int from = -1) const;
+    int lastIndexOf(const QByteArray &a, const int from = -1) const;
 
     bool contains(char c) const;
     bool contains(const char *a) const;
@@ -231,18 +231,18 @@ public:
 
     QList<QByteArray> split(char sep) const;
 
-    QByteArray repeated(int times) const;
+    QByteArray repeated(const int times) const;
 
 #ifndef QT_NO_CAST_TO_ASCII
     QT_ASCII_CAST_WARN QByteArray &append(const QString &s);
-    QT_ASCII_CAST_WARN QByteArray &insert(int i, const QString &s);
+    QT_ASCII_CAST_WARN QByteArray &insert(const int i, const QString &s);
     QT_ASCII_CAST_WARN QByteArray &replace(const QString &before, const char *after);
     QT_ASCII_CAST_WARN QByteArray &replace(char c, const QString &after);
     QT_ASCII_CAST_WARN QByteArray &replace(const QString &before, const QByteArray &after);
 
     QT_ASCII_CAST_WARN QByteArray &operator+=(const QString &s);
-    QT_ASCII_CAST_WARN int indexOf(const QString &s, int from = 0) const;
-    QT_ASCII_CAST_WARN int lastIndexOf(const QString &s, int from = -1) const;
+    QT_ASCII_CAST_WARN int indexOf(const QString &s, const int from = 0) const;
+    QT_ASCII_CAST_WARN int lastIndexOf(const QString &s, int const from = -1) const;
 #endif
 #ifndef QT_NO_CAST_FROM_ASCII
     inline QT_ASCII_CAST_WARN bool operator==(const QString &s2) const;
diff --git a/src/core/tools/qcryptographichash.cpp b/src/core/tools/qcryptographichash.cpp
index e6303a0de..ac3c94914 100644
--- a/src/core/tools/qcryptographichash.cpp
+++ b/src/core/tools/qcryptographichash.cpp
@@ -51,7 +51,6 @@ QT_BEGIN_NAMESPACE
 class QCryptographicHashPrivate
 {
 public:
-    QCryptographicHash::Algorithm method;
     MD4_CTX md4Context;
     MD5_CTX md5Context;
     SHA_CTX sha1Context;
@@ -59,6 +58,7 @@ public:
     SHA256_CTX sha256Context;
     SHA512_CTX sha384Context;
     SHA512_CTX sha512Context;
+    QCryptographicHash::Algorithm method;
     QByteArray result;
 };
 
@@ -93,7 +93,7 @@ public:
 /*!
   Constructs an object that can be used to create a cryptographic hash from data using \a method.
 */
-QCryptographicHash::QCryptographicHash(Algorithm method)
+QCryptographicHash::QCryptographicHash(QCryptographicHash::Algorithm method)
     : d(new QCryptographicHashPrivate)
 {
     d->method = method;
@@ -268,7 +268,7 @@ QByteArray QCryptographicHash::result() const
 /*!
   Returns the hash of \a data using \a method.
 */
-QByteArray QCryptographicHash::hash(const QByteArray &data, Algorithm method)
+QByteArray QCryptographicHash::hash(const QByteArray &data, QCryptographicHash::Algorithm method)
 {
     QCryptographicHash hash(method);
     hash.addData(data);