Intel® oneAPI DPC++/C++ Compiler Developer Guide and Reference

Development Reference Guides

Contents

x, Qx

Tells the compiler which processor features it may target, including which instruction sets and optimizations it may generate.

Syntax

Linux:
-x
code
Windows:
/Qx
code
Arguments
code
Specifies a feature set that the compiler can target, including which instruction sets and optimizations it may generate. Many of the following descriptions refer to Intel® Streaming SIMD Extensions (Intel® SSE) and Supplemental Streaming SIMD Extensions (Intel® SSSE). Possible values are:
ALDERLAKE
AMBERLAKE
BROADWELL
CANNONLAKE
CASCADELAKE
COFFEELAKE
COOPERLAKE
GOLDMONT
GOLDMONT-PLUS
HASWELL
ICELAKE-CLIENT
 (or
ICELAKE
)
ICELAKE-SERVER
IVYBRIDGE
KABYLAKE
KNL
KNM
ROCKETLAKE
SANDYBRIDGE
SAPPHIRERAPIDS
SILVERMONT
SKYLAKE
SKYLAKE-AVX512
TIGERLAKE
TREMONT
WHISKEYLAKE
May generate instructions for processors that support the specified Intel® processor or microarchitecture code name. Optimizes for the specified Intel® processor or microarchitecture code name.
Keywords
KNL
 and
SILVERMONT
 are only available on Windows* and Linux* systems.
Keyword
ICELAKE
 is deprecated and may be removed in a future release.
COMMON-AVX512
May generate Intel® Advanced Vector Extensions 512 (Intel® AVX-512) Foundation instructions, Intel® AVX-512 Conflict Detection Instructions (CDI), as well as the instructions enabled with CORE-AVX2. Optimizes for Intel® processors that support Intel® AVX-512 instructions.
CORE-AVX512
May generate Intel® Advanced Vector Extensions 512 (Intel® AVX-512) Foundation instructions, Intel® AVX-512 Conflict Detection Instructions (CDI), Intel® AVX-512 Doubleword and Quadword Instructions (DQI), Intel® AVX-512 Byte and Word Instructions (BWI) and Intel® AVX-512 Vector Length Extensions, as well as the instructions enabled with CORE-AVX2. Optimizes for Intel® processors that support Intel® AVX-512 instructions.
CORE-AVX2
May generate Intel® Advanced Vector Extensions 2 (Intel® AVX2), Intel® AVX, SSE4.2, SSE4.1, SSE3, SSE2, SSE, and SSSE3 instructions for Intel® processors. Optimizes for Intel® processors that support Intel® AVX2 instructions.
CORE-AVX-I
May generate
Float-16 conversion instructions and
the RDRND instruction, Intel® Advanced Vector Extensions (Intel® AVX), Intel® SSE4.2, SSE4.1, SSE3, SSE2, SSE, and SSSE3 instructions for Intel® processors. Optimizes for Intel® processors that support
Float-16 conversion instructions and
the RDRND instruction.
AVX
May generate Intel® Advanced Vector Extensions (Intel® AVX), Intel® SSE4.2, SSE4.1, SSE3, SSE2, SSE, and SSSE3 instructions for Intel® processors. Optimizes for Intel processors that support Intel® AVX instructions.
SSE4.2
May generate Intel® SSE4 Efficient Accelerated String and Text Processing instructions, Intel® SSE4 Vectorizing Compiler and Media Accelerator, and Intel® SSE3, SSE2, SSE, and SSSE3 instructions for Intel® processors. Optimizes for Intel processors that support Intel® SSE4.2 instructions.
SSE4.1
May generate Intel® SSE4 Vectorizing Compiler and Media Accelerator instructions for Intel® processors. May generate Intel® SSE4.1, SSE3, SSE2, SSE, and SSSE3 instructions for Intel processors that support Intel® SSE4.1 instructions.
ATOM_SSE4.2
May generate MOVBE instructions for Intel® processors, depending on the setting of option
-minstruction
 (Linux*) or
/Qinstruction
 (Windows*). May also generate Intel® SSE4.2, SSE3, SSE2, and SSE instructions for Intel processors. Optimizes for Intel Atom® processors that support Intel® SSE4.2 and MOVBE instructions.
This keyword is only available on Windows* and Linux* systems.
ATOM_SSSE3
May generate MOVBE instructions for Intel® processors, depending on the setting of option
-minstruction
 (Linux*) or
/Qinstruction
 (Windows*). May also generate SSSE3, Intel® SSE3, SSE2, and SSE instructions for Intel processors. Optimizes for Intel Atom® processors that support Intel® SSE3 and MOVBE instructions.
This keyword is only available on Windows* and Linux* systems.
SSSE3
May generate SSSE3 and Intel® SSE3, SSE2, and SSE instructions for Intel® processors. Optimizes for Intel processors that support SSSE3 instructions.
SSE3
May generate Intel® SSE3, SSE2, and SSE instructions for Intel® processors. Optimizes for Intel processors that support Intel® SSE3 instructions.
SSE2
May generate Intel® SSE2 and SSE instructions for Intel® processors. Optimizes for Intel processors that support Intel® SSE2 instructions.
Default
Windows* systems: None
Linux* systems: None
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 which processor features it may target, including which instruction sets and optimizations it may generate. It also enables optimizations in addition to Intel feature-specific optimizations.
The specialized code generated by this option may only run on a subset of Intel® processors.
The resulting executables created from these option
code
 values can only be run on Intel® processors that support the indicated instruction set.
The binaries produced by these
code
 values will run on Intel® processors that support the specified features.
Do not use
code
 values to create binaries that will execute on a processor that is not compatible with the targeted processor. The resulting program may fail with an illegal instruction exception or display other unexpected behavior.
Compiling the
function main()
 with any of the
code
 values produces binaries that display a fatal run-time error if they are executed on unsupported processors, including all non-Intel processors.
Compiler options
m
 and
arch
 produce binaries that should run on processors not made by Intel that implement the same capabilities as the corresponding Intel® processors.
The
-x
 and
/Qx
 options enable additional optimizations not enabled with options
-m
 or
/arch
.
On Windows systems, options
/Qx
 and /arch are mutually exclusive. If both are specified, the compiler uses the last one specified and generates a warning. Similarly, on Linux systems, options
-x
 and
-m
 are mutually exclusive. If both are specified, the compiler uses the last one specified and generates a warning.
All settings except SSE2 do a CPU check. However, if you specify option -O0 (Linux*) or option /Od (Windows*), no CPU check is performed.
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
Xcode:
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.