Performance Optimization and Tuning Techniques for IBM Power Systems Processors Including IBM POWER8

Compilers and optimization tools for C, C++, and Fortran

This chapter describes the optimization and tuning of the POWER8 processor-based servers by using compilers and tools. It covers the following topics:

•7.1, “Compiler versions and optimization levels” on page 142

•7.2, “Advanced compiler optimization techniques” on page 143

•7.3, “Capitalizing on POWER8 features with the XL and GCC compilers” on page 148

•7.4, “IBM Feedback Directed Program Restructuring” on page 160

•7.5, “Using the Advance Toolchain with IBM XLC and XLF” on page 169

•7.7, “Related publications” on page 171

7.1 Compiler versions and optimization levels

The IBM XL compilers ...