Either the VS2003 compilers used for 32 bit or the April 2005 SDK 64 bit compiler
used for 64 bit JDK apparently had a bug requiring this pragma :

// Enabling optimizations in this file causes incorrect code to be
// generated; can not figure out how to turn down optimization for one
// file in the IDE on Windows
#ifdef WIN32
# pragma optimize ( "", off )
#endif


For JDK 9 & higher built with VS2010 & higher we should reexamine the need for this #pragma and remove this deoptimization.