[llvm-dev] Question about ARM/aarch64 backend

[David Spickett via llvm-dev]

> Is aarch64 backend meant for 64-bit line of products and ARM has support for both A32 and T32?

Pretty much.

AArch64 (the architecture itself) started at Armv8. Anything before
that was 32 bit only (AArch32 if you will). So "AArch64" is for 64 bit
only, v8.0-a and above. "ARM" is for 32 bit only, from the latest
architecture versions all the way back to Armv6. (with some earlier
armv4 stuff but YMMV there)

So you can have an Armv8.5-a Arm target but you couldn't have an
Armv7-A AArch64 target.

And you'll also see some AArch64 capable CPUs listed for the ARM
backend because they can run 32 bit code as well.

On Wed, 13 Oct 2021 at 04:38, Rotate Right via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>
> Hi guys,
> What is the difference between aarch64 and ARM backend in the trunk?
> I see both of them having support of recent architectures so one doesn't seem to be deprecated over other.
> Is aarch64 backend meant for 64-bit line of products and ARM has support for both A32 and T32?
>
> Thanks.
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