Developer Guide and Reference

Contents

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

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.