Intel® C++ Compiler Classic Developer Guide and Reference

ID 767249
Date 12/16/2022
Public

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cpu_dispatch, cpu_specific

Provides the ability to write one or more versions of a function that execute only on a list of targeted processors (cpu_dispatch). Provides the ability to declare that a version of a function is targeted at particular types of processors (cpu_specific).

Syntax

Windows* OS:

__declspec(cpu_dispatch(cpuid, cpuid, ...))

__declspec(cpu_specific(cpuid))

Linux* OS:

__attribute__((cpu_dispatch(cpuid, cpuid, ...)))

__attribute__((cpu_specific(cpuid)))

Arguments

cpuid

Possible values are:

atom: Intel® Atom™ processors with Intel® Supplemental Streaming SIMD Extensions 3 (Intel® SSSE3)

atom_sse4_2: Intel® Atom™ processors with Intel® Streaming SIMD Extensions 4.2 (Intel® SSE4.2)

atom_sse4_2_movbe: Intel® Atom™ processors with Intel® Streaming SIMD Extensions 4.2 (Intel® SSE4.2) with MOVBE instructions enabled

broadwell: This is a synonym for core_5th_gen_avx

core_2nd_gen_avx: 2nd generation Intel® Core™ processor family with support for Intel® Advanced Vector Extensions (Intel® AVX)

core_3rd_gen_avx: 3rd generation Intel® Core™ processor family with support for Intel® Advanced Vector Extensions (Intel® AVX) including the RDRND instruction

core_4th_gen_avx: 4th generation Intel® Core™ processor family with support for Intel® Advanced Vector Extensions 2 (Intel® AVX2) including the RDRND instruction

core_4th_gen_avx_tsx: 4th generation Intel® Core™ processor family with support for Intel® Advanced Vector Extensions 2 (Intel® AVX2) including the RDRND instruction, and support for Intel® Transactional Synchronization Extensions (Intel® TSX)

core_5th_gen_avx: 5th generation Intel® Core™ processor family with support for Intel® Advanced Vector Extensions 2 (Intel® AVX2) including the RDSEED and Multi-Precision Add-Carry Instruction Extensions (ADX) instructions

core_5th_gen_avx_tsx: 5th generation Intel® Core™ processor family with support for Intel® Advanced Vector Extensions 2 (Intel® AVX2) including the RDSEED and Multi-Precision Add-Carry Instruction Extensions (ADX) instructions, and support for Intel® Transactional Synchronization Extensions (Intel® TSX)

core_aes_pclmulqdq: Intel® Core™ processors with support for Advanced Encryption Standard (AES) instructions and carry-less multiplication instruction

core_i7_sse4_2: Intel® Core™ i7 processors with Intel® Streaming SIMD Extensions 4.2 (Intel® SSE4.2) instructions

generic: Other Intel processors for IA-32 (for C++ only) or Intel® 64 architecture or compatible processors not provided by Intel Corporation

haswell: This is a synonym for core_4th_gen_avx

pentium: Intel® Pentium® processor

pentium_4: Intel® Pentium® 4 processors

pentium_4_sse3: Intel® Pentium® 4 processor with Intel® Streaming SIMD Extensions 3 (Intel® SSE3) instructions, Intel® Core™ Duo processors, Intel® Core™ Solo processors

pentium_ii: Intel® Pentium® II processors

pentium_iii: Intel® Pentium® III processors

pentium_iii_no_xmm_regs: Intel® Pentium® III processors with no XMM registers

pentium_m: Intel® Pentium® M processors

pentium_mmx: Intel® Pentium® processors with MMX™ technology

pentium_pro: Intel® Pentium® Pro processors

Description

Use the cpu_dispatch keyword to provide a list of targeted processors, along with an empty function body/function stub.

Use the cpu_specific keyword to declare each function version targeted at particular type of processor.

These features are available only for Intel processors based on IA-32 (for C++ only) or Intel® 64 architecture. They are not available for non-Intel processors. Applications built using the manual processor dispatch feature may be more highly optimized for Intel processors than for non-Intel processors.