CODEWITHSUNDEEP
c++ccompiler-errorscompilation
Momo
Momo

Reputation: 464

Why does march=native not work on Apple M1?

Whenever I try to compile any C++ program with march=native on a Macbook with a M1 chip, I get the following error when using clang:

clang: error: the clang compiler does not support '-march=native'

However, it used to work on an older Macbook with an Intel CPU. Does clang not support this architecture (yet)?

clang --version gives:

Apple clang version 12.0.0 (clang-1200.0.32.29)
Target: arm64-apple-darwin20.2.0

Upvotes: 32

Views: 38928

Answers (5)

Javier Moya
Javier Moya

Reputation: 1

another solutions is update clang with brew

lang: error: the clang compiler does not support '-march=native'

1° - Install llvm con brew

brew install llvm

2° - Check clang version

cd /opt/homebrew/opt/llvm
.clang --version

Result:

Homebrew clang version 15.0.6
Target: arm64-apple-darwin22.2.0
Thread model: posix
InstalledDir: /opt/homebrew/opt/llvm/bin

3° - modify path with the new version, for example add to .zshrc

export PATH="/opt/homebrew/opt/llvm/bin:$PATH"

Upvotes: 0

Nick Botticelli
Nick Botticelli

Reputation: 252

In Clang 15, -march=native now exists for Apple M1 (I personally use it).

Upvotes: 12

champagniac
champagniac

Reputation: 561

In Apple clang version 13.0.0, -mcpu=apple-m1 is now available.

Upvotes: 28

Guanyang Xue
Guanyang Xue

Reputation: 191

$ clang --print-supported-cpus
Apple clang version 12.0.5 (clang-1205.0.22.9)
Target: arm64-apple-darwin20.5.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin
Available CPUs for this target:

    a64fx
    apple-a10
    apple-a11
    apple-a12
    apple-a13
    apple-a14
    apple-a7
    apple-a8
    apple-a9
    apple-latest
    apple-s4
    apple-s5
    carmel
    cortex-a34
    cortex-a35
    cortex-a53
    cortex-a55
    cortex-a57
    cortex-a65
    cortex-a65ae
    cortex-a72
    cortex-a73
    cortex-a75
    cortex-a76
    cortex-a76ae
    cortex-a77
    cortex-a78
    cortex-x1
    cyclone
    exynos-m3
    exynos-m4
    exynos-m5
    falkor
    generic
    kryo
    lightning
    neoverse-e1
    neoverse-n1
    saphira
    thunderx
    thunderx2t99
    thunderx3t110
    thunderxt81
    thunderxt83
    thunderxt88
    tsv110
    vortex

-mcpu=apple-a14 might be the best one for M1.

Upvotes: 19

Malcolm MacLeod
Malcolm MacLeod

Reputation: 674

As far as I know this is not Apple M1 specific, it occurs also with clang for various other architectures (mostly various other arm processors). e.g. See this bug report here https://github.com/DMOJ/judge-server/issues/303

Basically every build of clang for a new architecture must choose to provide defaults for "march=native" for the target for which the compiler is built or not; and if not then you will see this error message. Even for those arm processors who do have optimisation targets you often have to use specifically "-mcpu=xxx" instead of "-march".

e.g. For the iphone you would use -mcpu=apple-a11 -mcpu=apple-a12 etc.

However no such target has been implemented yet for Apple M1

Upvotes: 8

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