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JULY 29, 2026
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aarch64 Performance Win

AArch64: Enable SVE AES instructions in streaming mode

AArch64 SVE AES instructions are now usable in streaming mode with FEAT_SSVE_AES.

This commit enables the AArch64 SVE AES instructions (AESE, AESD, AESMC, AESIMC) to function in Streaming SVE mode, by leveraging the FEAT_SSVE_AES feature. The changes involve updating CPP builtins, DEF files, and model files to correctly identify and utilize these AES instructions in their streaming-compatible form. Tests are also updated to reflect this new capability.

In Details

This change enables FEAT_SSVE_AES, allowing existing Streaming SVE (SSVE) instructions to be used for AES operations. The update modifies SVE2-AES built-in definitions and related SVE2 modes in the AArch64 backend. Specifically, the TARGET_SVE2_AES macro is renamed to TARGET_SVE_AES to reflect its broader applicability in SSVE mode, and test cases are adjusted accordingly.

For Context
SVE
Scalable Vector Extension. An ARM architecture feature that allows vector registers to have a flexible length, adapting to the underlying hardware. This enables code to run efficiently across a range of devices without recompilation.
Streaming SVE (SSVE)
A mode of operation for ARM's Scalable Vector Extension where vector operations can be pipelined more effectively, improving performance for certain workloads, particularly those involving continuous data streams.
FEAT_SSVE_AES
A specific ARM architecture feature or extension that enables AES (Advanced Encryption Standard) instructions to be used within the Streaming SVE mode.
AArch64
The 64-bit execution state of the ARMv8-A architecture and subsequent versions. It is the primary architecture for modern high-performance ARM processors.
intrinsics
Special functions or assembly language mnemonics that expose hardware capabilities directly to the C/C++ programming language. They allow for fine-grained control over hardware features like vector operations.
Filed Under: aarch64svecryptographyoptimization