diff --git a/applications/test/PackedList/Make/options b/applications/test/PackedList/Make/options
index e69de29bb2..42da6e3418 100644
--- a/applications/test/PackedList/Make/options
+++ b/applications/test/PackedList/Make/options
@@ -0,0 +1,7 @@
+/*
+  check for consistent behaviour with non-optimized code
+  */
+
+EXE_INC = \
+    -DFULLDEBUG -g -O0
+
diff --git a/applications/test/PackedList/PackedListTest.C b/applications/test/PackedList/PackedListTest.C
index 0c8528bd1c..9bf29923fe 100644
--- a/applications/test/PackedList/PackedListTest.C
+++ b/applications/test/PackedList/PackedListTest.C
@@ -34,9 +34,46 @@ Description
 #include "IOstreams.H"
 #include "IFstream.H"
 #include "PackedBoolList.H"
+#include <climits>
+
 
 using namespace Foam;
 
+template<unsigned nBits>
+inline void reportInfo()
+{
+    unsigned offset = PackedList<nBits>::packing();
+
+    unsigned useSHL = ((1u << (nBits * offset)) - 1);
+    unsigned useSHR = (~0u >> (sizeof(unsigned)*CHAR_BIT - nBits * offset));
+
+    Info<< nl
+        << "PackedList<" << nBits << ">" << nl
+        << " max_value: " << PackedList<nBits>::max_value() << nl
+        << " packing: " << PackedList<nBits>::packing() << nl
+        << " utilization: " << (nBits * offset) << nl;
+
+    Info<< " Masking:" << nl
+        << "  shift << " << unsigned(nBits * offset) << nl
+        << "  shift >> " << unsigned((sizeof(unsigned)*CHAR_BIT) - nBits * offset)
+        << nl;
+
+    hex(Info);
+    Info<< "   maskLower: " << PackedList<nBits>::maskLower(PackedList<nBits>::packing())
+        << nl
+        << "      useSHL: " << useSHL << nl
+        << "      useSHR: " << useSHR << nl;
+
+    if (useSHL != useSHR)
+    {
+        Info<< "WARNING:  different results for SHL and SHR" << nl;
+    }
+
+    Info<< nl;
+    dec(Info);
+}
+
+
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 //  Main program:
 
@@ -45,16 +82,56 @@ int main(int argc, char *argv[])
     argList::noParallel();
     argList::validArgs.insert("file .. fileN");
 
+    argList::validOptions.insert("mask", "");
     argList::validOptions.insert("count", "");
     argList::validOptions.insert("info", "");
 
     argList args(argc, argv, false, true);
 
-    if (args.additionalArgs().empty())
+
+    if (args.optionFound("mask"))
+    {
+        Info<< "bit width: " << unsigned(sizeof(unsigned)*CHAR_BIT) << endl;
+        reportInfo<1>();
+        reportInfo<2>();
+        reportInfo<3>();
+        reportInfo<4>();
+        reportInfo<5>();
+        reportInfo<6>();
+        reportInfo<7>();
+        reportInfo<8>();
+        reportInfo<9>();
+        reportInfo<10>();
+        reportInfo<11>();
+        reportInfo<12>();
+        reportInfo<13>();
+        reportInfo<14>();
+        reportInfo<15>();
+        reportInfo<16>();
+        reportInfo<17>();
+        reportInfo<18>();
+        reportInfo<19>();
+        reportInfo<20>();
+        reportInfo<21>();
+        reportInfo<22>();
+        reportInfo<23>();
+        reportInfo<24>();
+        reportInfo<25>();
+        reportInfo<26>();
+        reportInfo<27>();
+        reportInfo<28>();
+        reportInfo<29>();
+        reportInfo<30>();
+        reportInfo<31>();
+
+        return 0;
+    }
+    else if (args.additionalArgs().empty())
     {
         args.printUsage();
     }
 
+
     forAll(args.additionalArgs(), argI)
     {
         const string& srcFile = args.additionalArgs()[argI];
@@ -62,6 +139,7 @@ int main(int argc, char *argv[])
 
         IFstream ifs(srcFile);
         List<label> rawLst(ifs);
+
         PackedBoolList packLst(rawLst);
 
         Info<< "size: " << packLst.size() << nl;
@@ -72,11 +150,11 @@ int main(int argc, char *argv[])
             forAll(rawLst, elemI)
             {
                 if (rawLst[elemI])
-                {                    
+                {
                     rawCount++;
-                }                
+                }
             }
-            Info<< "raw count: " << rawCount << nl            
+            Info<< "raw count: " << rawCount << nl
                 << "packed count: " << packLst.count() << nl;
         }
 
@@ -84,7 +162,7 @@ int main(int argc, char *argv[])
         {
             packLst.print(Info);
         }
-        
+
         Info<< nl;
         IOobject::writeDivider(Info);
     }
diff --git a/src/OpenFOAM/containers/Lists/PackedList/PackedList.C b/src/OpenFOAM/containers/Lists/PackedList/PackedList.C
index 87ced9504f..ecf64f861a 100644
--- a/src/OpenFOAM/containers/Lists/PackedList/PackedList.C
+++ b/src/OpenFOAM/containers/Lists/PackedList/PackedList.C
@@ -204,19 +204,15 @@ Foam::Ostream& Foam::PackedList<nBits>::iteratorBase::print(Ostream& os) const
 template<unsigned nBits>
 Foam::Ostream& Foam::PackedList<nBits>::print(Ostream& os) const
 {
-    os  << "PackedList<" << label(nBits) << ">"
+    const label packLen = packedLength(size_);
+
+    os  << "PackedList<" << nBits << ">"
         << " max_value:" << max_value()
         << " packing:"   << packing() << nl
-        << "values: " << size_ << "/" << capacity() << "( ";
-    forAll(*this, i)
-    {
-        os << get(i) << ' ';
-    }
-
-    label packLen = packedLength(size_);
-
-    os  << ")\n"
-        << "storage: " << packLen << "/" << StorageList::size() << "( ";
+        << " count: "     << count() << nl
+        << " size/capacity: " << size_ << "/" << capacity() << nl
+        << " storage/capacity: " << packLen << "/" << StorageList::size()
+        << "\n(\n";
 
     // mask value for complete segments
     unsigned int mask = maskLower(packing());
@@ -240,7 +236,7 @@ Foam::Ostream& Foam::PackedList<nBits>::print(Ostream& os) const
             }
         }
 
-        for (unsigned int testBit = (1 << max_bits()); testBit; testBit >>= 1)
+        for (unsigned int testBit = (1u << max_bits()); testBit; testBit >>= 1)
         {
             if (mask & testBit)
             {
@@ -250,15 +246,15 @@ Foam::Ostream& Foam::PackedList<nBits>::print(Ostream& os) const
                 }
                 else
                 {
-                    os << '0';
+                    os << '-';
                 }
             }
             else
             {
-                os << '.';
+                os << 'x';
             }
         }
-        cout << ' ';
+        os << '\n';
     }
     os << ")\n";
 
diff --git a/src/OpenFOAM/containers/Lists/PackedList/PackedListI.H b/src/OpenFOAM/containers/Lists/PackedList/PackedListI.H
index 711ed03db6..df7786f61b 100644
--- a/src/OpenFOAM/containers/Lists/PackedList/PackedListI.H
+++ b/src/OpenFOAM/containers/Lists/PackedList/PackedListI.H
@@ -40,7 +40,7 @@ inline unsigned int Foam::PackedList<nBits>::max_bits()
 template<unsigned nBits>
 inline unsigned int Foam::PackedList<nBits>::max_value()
 {
-    return (1 << nBits) - 1;
+    return (1u << nBits) - 1;
 }
 
 
@@ -54,7 +54,10 @@ inline unsigned int Foam::PackedList<nBits>::packing()
 template<unsigned nBits>
 inline unsigned int Foam::PackedList<nBits>::maskLower(unsigned offset)
 {
-    return (1 << (nBits * offset)) - 1;
+    // return (1u << (nBits * offset)) - 1;
+    // The next one works more reliably with overflows
+    // eg, when compiled without optimization
+    return (~0u >> ( sizeof(StorageType)*CHAR_BIT - nBits * offset));
 }
 
 
@@ -581,7 +584,7 @@ inline void Foam::PackedList<nBits>::resize
             if (fill & ~max_value())
             {
                 // overflow is max_value, fill everything
-                fill = ~0;
+                fill = ~0u;
             }
             else
             {
@@ -847,7 +850,7 @@ inline void Foam::PackedList<nBits>::operator=(const unsigned int val)
         if (fill & ~max_value())
         {
             // treat overflow as max_value
-            fill = ~0;
+            fill = ~0u;
         }
         else
         {