Support for POWER7 processors

IBM® XL C/C++ for Linux®, V11.1 supports POWER7 processors.

The new features and enhancements introduced in support for the POWER7 processors, fall under the following four categories:

Vector scalar extension data types and intrinsic functions

This release of the compiler supports the Vector Scalar eXtension (VSX) instruction set in the POWER7 processors. New data types and intrinsic functions are introduced to support the VSX instructions. With the VSX intrinsic functionsand the original Vector Multimedia eXtension (VMX) intrinsic functions, you can efficiently manipulate vector operations in your application.

For more information about the VSX data types and intrinsic functions, see Vector types and Vector built-in functions.

Mathematical Acceleration Subsystem (MASS) libraries for POWER7 processors

Vector libraries

The vector MASS library libmassvp7.a contains vector functions that have been tuned for the POWER7 architecture. The functions can be used in either 32-bit mode or 64-bit mode.

Functions supporting previous POWER® processors, either single-precision or double-precision, are included for POWER7 processors.

The following new functions are added, in both single-precision and double-precision function groups:
  • exp2
  • exp2m1
  • log21p
  • log2

For more information about the vector libraries, see Using the vector libraries.

SIMD libraries

The MASS SIMD library libmass_simdp7.a contains an accelerated set of frequently used math intrinsic functions that provide improved performance over the corresponding standard system library functions.

For more information about the SIMD libraries, see Using the SIMD library for POWER7.

POWER7 hardware intrinsics

New hardware intrinsics are added to support the following POWER7 processor features:
  • new POWER7 prefetch extensions and cache control
  • new POWER7 hardware instructions

For more information, see Built-in functions new for this release.

New compiler options for POWER7 processors

New arch and tune compiler options

The -qarch compiler option specifies the processor architecture for which code is generated. The -qtune compiler option tunes instruction selection, scheduling, and other architecture-dependent performance enhancements to run best on a specific hardware architecture.

-qarch=pwr7 produces object code containing instructions that will run on the POWER7 hardware platforms. With -qtune=pwr7, optimizations are tuned for the POWER7 hardware platforms.

For more information, see -qarch and -qtune.