Optimization and performance
XL C/C++ offers a number of optimization and performance-tuning features that exploit all PowerPC systems. The -qarch and -qtune compiler options further tune generated application code to fully exploit the performance capabilities of the PowerPC 440d processor and its Double Hummer floating-point unit used in the PowerPC 450d processor and its Double Hummer floating-point unit used in Blue Gene/P systems. In addition the compiler provides a versatile set of built-in functions capable of manipulating complex data types, and you can include calls to these built-in functions in your program code to further exploit the capabilities of the PowerPC 440, 440d, 450, and 450d processors.
Mathematical Acceleration Subsystem (MASS)
XL C/C++ provides additional scalar and vector functions as part of the Mathematical Acceleration Subsystem (MASS). MASS consists of libraries of tuned mathematical intrinsic functions that offer improved performance over the standard mathematical library routines.

