The OpenPOWER ELF V2 application binary interface (ABI): Chapter 6. Vector Programming Interfaces and Appendix A. Predefined Functions for Vector Programming document the current and proposed vector built-ins we expect all C/C++ compilers implement. Some of these operations are endian sensitive and the compiler needs to make corresponding adjustments as it generates code for endian sensitive built-ins. There is a good overview for this in the OpenPOWER ABI Section 6.4. Vector Built-in Functions. Appendix A is organized (sorted) by built-in name, output type, then parameter types. Most built-ins are overloaded as the named operation (vec_add, vec_sub, vec_mul, vec_cmpeq, ...) applies to multiple types. So the vec_add built-in applies to all the signed and unsigned integer types (char, short, in, and long) plus float and double floating-point types. The compiler looks at the parameter type to select the vector instruction (or instruction sequence) that implements the add operation on that type. The compiler infers the output result type from the operation and input parameters and will complain if the target variable type is not compatible. Some examples: This is one key difference between PowerISA built-ins and Intel Intrinsics (Intel Intrinsics are not overloaded and include type information in the name). This is why it is so important to understand the vector element types and to add the appropriate type casts to get the correct results. The de facto standard implementation in GCC is defined in the include file <altivec.h> and documented in the GCC online documentation in 6.59.20 PowerPC AltiVec Built-in Functions. The header file name and section title reflect the origin of the Vector Facility, but recent versions of GCC altivec.h include built-ins for newer PowerISA 2.06 and 2.07 VMX plus VSX extensions. This is a work in progress where your  (older) distro GCC compiler may not include built-ins for the latest PowerISA 3.0 or ABI edition. So before you use a built-in you find in the ABI Appendix A, check the specific GCC online documentation for the GCC version you are using.