Syntax

To specify a target architecture, use:

-march=name

-march=name[+[no]feature+…] (for architectures with optional extensions)

Where:

name

Specifies the architecture.

To view a list of all the supported architectures, use:

-march=list

The following are valid -march values:

armv8-a

Arm^®v8 application architecture profile. Valid with both --target=aarch64-arm-none-eabi and --target=arm-arm-none-eabi.

armv8.1-a

Armv8.1 application architecture profile. Valid with both --target=aarch64-arm-none-eabi and --target=arm-arm-none-eabi.

armv8.2-a

Armv8.2 application architecture profile. Valid with both --target=aarch64-arm-none-eabi and --target=arm-arm-none-eabi.

armv8.3-a

Armv8.3 application architecture profile. Valid with both --target=aarch64-arm-none-eabi and --target=arm-arm-none-eabi.

armv8.4-a

Armv8.4 application architecture profile. Valid with both --target=aarch64-arm-none-eabi and --target=arm-arm-none-eabi.

armv8.5-a

Armv8.5 application architecture profile. Valid with both --target=aarch64-arm-none-eabi and --target=arm-arm-none-eabi.

[ALPHA] armv8.6-a

Armv8.6 application architecture profile. Valid with both --target=aarch64-arm-none-eabi and --target=arm-arm-none-eabi.

armv8-r

Armv8 real-time architecture profile. Only valid with --target=arm-arm-none-eabi.

armv8-m.base

Armv8 microcontroller architecture profile without the Main Extension. Derived from the Armv6‑M architecture. Only valid with --target=arm-arm-none-eabi.

armv8-m.main

Armv8 microcontroller architecture profile with the Main Extension. Derived from the Armv7‑M architecture. Only valid with --target=arm-arm-none-eabi.

armv8.1-m.main

Armv8.1 microcontroller architecture profile with the Main Extension. Only valid with --target=arm-arm-none-eabi.

armv7-a

Armv7 application architecture profile. Only valid with --target=arm-arm-none-eabi.

armv7-r

Armv7 real-time architecture profile. Only valid with --target=arm-arm-none-eabi.

armv7-m

Armv7 microcontroller architecture profile. Only valid with --target=arm-arm-none-eabi.

armv7e-m

Armv7 microcontroller architecture profile with DSP extension. Only valid with --target=arm-arm-none-eabi.

armv6-m

Armv6 microcontroller architecture profile. Only valid with --target=arm-arm-none-eabi.

feature

Is an optional architecture feature that might be enabled or disabled by default depending on the architecture or processor.

Note

In general, if an architecture supports the optional feature, then this optional feature is enabled by default. For AArch32 state inputs only, you can use fromelf --decode_build_attributes to determine whether the optional feature is enabled.

+feature enables the feature if it is disabled by default. +feature has no effect if the feature is already enabled by default.

+nofeature disables the feature if it is enabled by default. +nofeature has no effect if the feature is already disabled by default.

Use +feature or +nofeature to explicitly enable or disable an optional architecture feature.

For targets in AArch64 state, you can specify one or more of the following features if the architecture supports it:

• aes - Cryptographic Extension. See Cryptographic Extensions for more information.
• crc - CRC extension.
• crypto - Cryptographic Extension. See Cryptographic Extensions for more information.
• dotprod - Enables the SDOT and UDOT instructions. Supported in the Armv8.2 and later Application profile architectures, and is optional in Armv8.2 and Armv8.3.
• fp - Floating-point extension. See Floating-point extensions for more information.
• fp16 - Armv8.2-A half-precision floating-point extension. See Floating-point extensions for more information.
• [ALPHA] bf16 - Armv8.6-A BFloat16 floating-point extension. See Floating-point extensions for more information. This extension is optional in Armv8.2 and later Application profile architectures.
• fp16fml - Half-precision floating-point multiply with add or multiply with subtract extension. Supported in the Armv8.2 and later Application profile architectures, and is optional in Armv8.2-A and Armv8.3-A. See Floating-point extensions for more information.
• [ALPHA] i8mm, f32mm, f64mm - Armv8.6-A Matrix Multiply extension. This extension is optional in Armv8.2 and later Application profile architectures. See Matrix Multiplication Extension for more information.
• memtag - Armv8.5-A memory tagging extension. See -fsanitize.
• profile - Armv8.2-A statistical profiling extension.
• ras - Reliability, Availability, and Serviceability extension.
• predres - Enable instructions to prevent data prediction. See Prevention of Speculative execution and data prediction for more information.
• rcpc - Release Consistent Processor Consistent extension. This extension applies to Armv8.2 and later Application profile architectures.
• rng - Armv8.5-A random number generation extension.
• sb - Enable the speculation barrier SB instruction. See Prevention of Speculative execution and data prediction for more information.
• ssbs - Enable the Speculative Store Bypass Safe instructions. See Prevention of Speculative execution and data prediction for more information.
• sha2 - Cryptographic Extension. See Cryptographic Extensions for more information.
• sha3 - Cryptographic Extension. See Cryptographic Extensions for more information.
• simd - Advanced SIMD extension.
• sm4 - Cryptographic Extension. See Cryptographic Extensions for more information.
• sve - Scalable Vector Extension. This extension applies to Armv8 and later Application profile architectures. See Scalable Vector Extension for more information.
• sve2 - Scalable Vector Extension 2. This extension is part of the early support for Future Architecture Technologies, and applies to Armv8 and later Application profile architectures. See Scalable Vector Extension for more information.
• tme - Transactional Memory Extension. This extension is part of the early support for Future Architecture Technologies, and applies to Armv8 and later Application profile architectures. See Transactional Memory Extension for more information.

For targets in AArch32 state, you can specify one or more of the following features if the architecture supports it:

• crc - CRC extension for architectures Armv8 and above.
• dotprod - Enables the VSDOT and VUDOT instructions. Supported in Armv8.2 and later Application profile architectures, and is optional in Armv8.2 and Armv8.3.
• dsp - DSP extension for the Armv8‑M.mainline architecture.
• fp16 - Armv8.2-A half-precision floating-point extension. See Floating-point extensions for more information.
• [ALPHA] bf16 - Armv8.6-A BFloat16 floating-point extension. See Floating-point extensions for more information. This extension is optional in Armv8.2 and later Application profile architectures.
• fp16fml - Half-precision floating-point multiply with add or multiply with subtract extension. Supported in the Armv8.2 and later Application profile architectures, and is optional in Armv8.2-A and Armv8.3-A. See Floating-point extensions for more information.
• [ALPHA] i8mm - Armv8.6-A Matrix Multiply extension. This extension is optional in Armv8.2 and later Application profile architectures. See Matrix Multiplication Extension for more information.
• mve - MVE extension for the Armv8.1-M architecture profile. See M-profile Vector Extension for more information.
• ras - Reliability, Availability, and Serviceability extension.
• sb - Enable the speculation barrier SB instruction. See Prevention of Speculative execution and data prediction for more information.

Note

For targets in AArch32 state, you can use -mfpu to specify the support for floating-point, Advanced SIMD, and Cryptographic Extensions.