# xHost, QxHost

Tells the compiler to generate instructions for the highest instruction set available on the compilation host processor.

## Syntax

Linux: | -xHost

Windows: | /QxHost

## Arguments

None

## Default

Windows* systems: None Linux* systems: None macOS* systems: -xSSSE3 | On Windows systems, if neither /Qx nor /arch is specified, the default is /arch:SSE2. On Linux systems, if neither -x nor -m is specified, the default is -msse2.

## Description

This option tells the compiler to generate instructions for the highest instruction set available on the compilation host processor.

The instructions generated by this compiler option differ depending on the compilation host processor.

The following table describes the effects of specifying the [Q]xHost option and it tells whether the resulting executable will run on processors different from the host processor.

Descriptions in the table refer to Intel® Advanced Vector Extensions 2 (Intel® AVX2), Intel® Advanced Vector Extensions (Intel® AVX), Intel® Streaming SIMD Extensions (Intel® SSE), and Supplemental Streaming SIMD Extensions (SSSE).

Instruction Set of Host Processor | Effects When the -xHost or /QxHost Compiler Option is Specified
--- | ---
Intel® AVX2 | When compiling on Intel® processors: Corresponds to option [Q]xCORE-AVX2. The generated executable will not run on non-Intel processors and it will not run on Intel® processors that do not support Intel® AVX2 instructions. When compiling on non-Intel processors: Corresponds to option -march=core-avx2 (Linux*) or /arch:CORE-AVX2 (Windows*). The generated executable will run on Intel® processors and non-Intel processors that support at least Intel® AVX2 instructions.. You may see a run-time error if the run-time processor does not support Intel® AVX2 instructions.
Intel® AVX | When compiling on Intel® processors: Corresponds to option [Q]xAVX. The generated executable will not run on non-Intel processors and it will not run on Intel® processors that do not support Intel® AVX instructions. When compiling on non-Intel processors: Corresponds to option -mavx (Linux) or /arch:AVX (Windows). The generated executable will run on Intel® processors and non-Intel processors that support at least Intel® AVX instructions. You may see a run-time error if the run-time processor does not support Intel® AVX instructions.
Intel® SSE4.2 | When compiling on Intel® processors: Corresponds to option [Q]xSSE4.2. The generated executable will not run on non-Intel processors and it will not run on Intel® processors that do not support Intel® SSE4.2 instructions. When compiling on non-Intel processors: Corresponds to option -msse4.2 (Linux) or /arch:SSE4.2 (Windows). The generated executable will run on Intel® processors and non-Intel processors that support at least Intel® SSE4.2 instructions. You may see a run-time error if the run-time processor does not support Intel® SSE4.2 instructions.
Intel® SSE4.1 | When compiling on Intel® processors: Corresponds to option [Q]xSSE4.1. The generated executable will not run on non-Intel processors and it will not run on Intel® processors that do not support Intel® SSE4.1 instructions. When compiling on non-Intel processors: Corresponds to option -msse4.1 (Linux) or /arch:SSE4.1 (Windows). The generated executable will run on Intel® processors and non-Intel processors that support at least Intel® SSE4.1 instructions. You may see a run-time error if the run-time processor does not support Intel® SSE4.1 instructions.
SSSE3 | When compiling on Intel® processors: Corresponds to option [Q]xSSSE3. The generated executable will not run on non-Intel processors and it will not run on Intel® processors that do not support SSSE3 instructions. When compiling on non-Intel processors: Corresponds to option -mssse3 (Linux) or /arch:SSSE3 (Windows). The generated executable will run on Intel® processors and non-Intel processors that support at least SSSE3 instructions. You may see a run-time error if the run-time processor does not support SSSE3 instructions.
Intel® SSE3 | When compiling on Intel® processors: Corresponds to option [Q]xSSE3. The generated executable will not run on non-Intel processors and it will not run on Intel® processors that do not support Intel® SSE3 instructions. When compiling on non-Intel processors: Corresponds to option -msse3 (Linux) or /arch:SSE3 (Windows). The generated executable will run on Intel® processors and non-Intel processors that support at least Intel® SSE3 instructions. You may see a warning run-time error if the run-time processor does not support Intel® SSE3 instructions.
Intel® SSE2 | When compiling on Intel® processors or non-Intel processors: Corresponds to option -msse2 (Linux and macOS*) or /arch:SSE2 (Windows). The generated executable will run on Intel® processors and non-Intel processors that support at least Intel® SSE2 instructions. You may see a run-time error if the run-time processor does not support Intel® SSE2 instructions.

For more information on other settings for option [Q]x, see that option description.

Product and Performance Information
Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex. Notice revision #20201201

## IDE Equivalent

Visual Studio: Code Generation > Intel Processor-Specific Optimization

Eclipse: Code Generation > Intel Processor-Specific Optimization

## Alternate Options

None

Parent topic: Code Generation Options

## See Also

x, Qx compiler option
m compiler option
arch compiler option