1469790 - Allow NEON autovectorization throughout the tree for NEON-required ARMv7 (e.g. Android)

Status: RESOLVED FIXED

(Firefox Build System :: Toolchains, enhancement)

Description

[Henri Sivonen (:hsivonen) (not reading bugmail until 2025-02-06)]

According to bug 1397807 comment 17, we don't compile all C++ code with NEON enabled when compiling for ARMv7 Android despite only supporting Android devices that have NEON available.

When Firefox is built with the assumption that NEON is unconditionally available, we might as well tell the compiler that NEON is available for all compilation units in case the autovectorizer manages to do something beneficial.

Comment 1

[Kim Moir [:kmoir] ET]

Snorp, do you have anyone on your team that might look at this?

Comment 2

[Mike Hommey [:glandium]]

Attachment: Bug 1469790 - Build for NEON by default when targetting Android arm.

The media/libpng/moz.build file overrides the C standard used via
-std=c89, per bug 1371266, which conflicts with the use of the
arm_neon.h header: compilation fails on the inline keyword, which didn't
exist in C89. We thus "bump" to the GNU89 standard, which is C89+GNU
extensions, including inline.

Review commit: https://reviewboard.mozilla.org/r/253286/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/253286/

Comment 3

[Nick Alexander :nalexander [he/him]]

Comment on attachment 8988033 [details]
Bug 1469790 - Build for NEON by default when targetting Android arm.

https://reviewboard.mozilla.org/r/253286/#review260062

Sure.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9d09683ea3d8
Build for NEON by default when targetting Android arm. r=nalexander

Comment 5

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/9d09683ea3d8