[PATCH v4 0/1] sysdeps/x86: prefer EVEX on Hygon by setting Prefer_No_AVX512

[Jiamei Xie]

This patch biases the ifunc selector on Hygon model 0x7 to prefer EVEX over AVX512,
by enabling the Prefer_No_AVX512 flag.

In our tests, AVX-512 variants on Hygon model 0x7 often perform worse than EVEX, so
this change attempts to guide the selector toward the better-performing path for that
specific model.

---
v1: https://patchwork.ozlabs.org/project/glibc/cover/20251013130222.123330-1-xiejiamei@hygon.cn/
v2: https://sourceware.org/pipermail/libc-alpha/2025-October/171082.html
v3: https://sourceware.org/pipermail/libc-alpha/2025-November/172225.html

Changes in v4:
 * Remove extra asterisk in comment

Changes in v3:
 * Rebase

Changes in v2:
 * Do both the vendor ID check and the model check
 * Wrap lines not longer than 79 characters.
 * Reword commit msg and comment.


Xie jiamei (1):
  Set Prefer_No_AVX512 flag for hygon platform

 sysdeps/x86/cpu-features.c | 7 +++++++
 1 file changed, 7 insertions(+)

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2.42.0