951981 – dev-cpp/highway: Fails to build on arm64 with cpu_flags_arm_neon

Bug 951981 - dev-cpp/highway: Fails to build on arm64 with cpu_flags_arm_neon

Summary: dev-cpp/highway: Fails to build on arm64 with cpu_flags_arm_neon

Status:	UNCONFIRMED

Alias:	None

Product:	Gentoo Linux
Classification:	Unclassified
Component:	Current packages (show other bugs)
Hardware:	All Linux

Importance:	Normal normal
Assignee:	Daniel Novomeský

URL:
Whiteboard:
Keywords:

Depends on:
Blocks:

Reported:	2025-03-24 18:55 UTC by benoit.dufour
Modified:	2025-03-26 15:35 UTC (History)
CC List:	2 users (show)

See Also:
Package list:
Runtime testing required:	---

Attachments
build.log (sr_hc_lx2_highway_build.log,21.98 KB, text/x-log) 2025-03-24 18:55 UTC, benoit.dufour	Details
emerge --info (emerge_info_sr_lx2_arm64.txt,8.03 KB, text/plain) 2025-03-24 18:57 UTC, benoit.dufour	Details
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Description benoit.dufour 2025-03-24 18:55:34 UTC

Created attachment 922368 [details]
build.log

See the logs.

Comment 1 benoit.dufour 2025-03-24 18:57:16 UTC

Created attachment 922369 [details]
emerge --info

Comment 2 benoit.dufour 2025-03-26 15:35:53 UTC

A closer look to the logs led me to think that those flags:
 -march=armv7-a -mfpu=neon-vfpv4 -mfloat-abi=hard 
are generated by this snippet of the CMakeLists.txt

https://github.com/google/highway/blob/99bb05378be47b4c21baef4c8ff0db831a2a88f1/CMakeLists.txt#L432C7-L432C21

So HWY_CMAKE_ARM7 which is turned on by the ebuild in multilib_src_configure().

And so it is trying to compile for armv7-a instead of armv8-a.
This behaviour is kinda bad since it doesn't take account for aarch64.