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[FMV] Add support-level table and remove __ARM_ACLE_VERSION #441

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[FMV] Add support-level table and remove __ARM_ACLE_VERSION #441

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103 changes: 69 additions & 34 deletions main/acle.md
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Expand Up @@ -1499,32 +1499,9 @@ enclose them in parentheses if they are not simple constants.

## Testing for Arm C Language Extensions

`__ARM_ACLE` is defined as the version of this specification that is
implemented, formatted as `{YEAR}{QUARTER}{PATCH}`. The `YEAR` segment is
composed of 4 digits, the `QUARTER` segment is composed of 1 digit, and
the `PATCH` segment is also composed of 1 digit.

For example:

- An implementation based on the version 2023 Q2 of the ACLE with no
further patch releases will define `__ARM_ACLE` as `202320`.
- An implementation based on a hypothetical version 2024 Q3 of the ACLE
with two patch releases will define `__ARM_ACLE` as `202432`.

NOTE: Previously, the macro followed the previous versioning scheme and
was defined as `100 * major_version + minor_version`, which was the
version of this specification implemented. For instance, an implementation
implementing version 2.1 of the ACLE specification defined `__ARM_ACLE`
as `201`.

`__ARM_ACLE_VERSION(year, quarter, patch)` is defined to express a given
ACLE version. Returns with the version number in the same format as the
`__ARM_ACLE` does. Checking the minimum required ACLE version could be
written as:

``` c
#if __ARM_ACLE >= __ARM_ACLE_VERSION(2024, 1, 0)
```
`__ARM_ACLE` is defined when the implementation supports the Arm C
Language Extensions. For compatibility with existing code, its
recommended value is 202420.

@DanielKristofKiss DanielKristofKiss Jul 21, 2026

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why not 202520? ( or whatever version was the last ACLE release before this change )

@CarolineConcatto CarolineConcatto Jul 22, 2026 •
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That is a recommendation based on the latest implementation that is set in llvm:
Builder.defineMacro("__ARM_ACLE", Twine(ARM_ACLE_VERSION(2024, 2, 0)));
But if there is another compile with other version, I think the recommendation could be ignored.


## Endianness

Expand Down Expand Up @@ -2998,14 +2975,8 @@ following:
versioning mechanism described in this section is supported by the
compiler and it is enabled.

`__FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL` is defined to the currently supported
version of the ACLE. The value and the format are the same as the `__ARM_ACLE`.

For example, it can be implemented as:

``` c
#define __FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL __ARM_ACLE_VERSION(2024, 3, 0)
```
`__FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL` is defined to a value corresponding to the
support levels listed in [Function Multi Versioning feature availability](#function-multi-versioning-feature-availability).

### Target version strings

Expand Down Expand Up @@ -3130,6 +3101,70 @@ The following table lists the architectures feature mapping for AArch64.

The tables are sorted by priority, starting from features of lowest priority ending with features of highest priority.

### Function Multi Versioning feature availability

The following table lists the Function Multi Versioning support level at
which each target version name became available.

A Function Multi Versioning target version name is supported when
`__HAVE_FUNCTION_MULTI_VERSIONING` is defined to `1` and
`__FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL` is greater than or equal to
the support level listed for that name. A given support level includes all
target version names from earlier support levels unless documented otherwise.


| **Name** | **Available from support level** |
| ------------- | -------------------------------- |
| default | **202210** |
| sha1 | 202210 |
| aes | 202210 |
| vmull | 202210 |
| rng | 202210 |
| flagm | 202210 |
| flagm2 | 202210 |
| lse | 202210 |
| dotprod | 202210 |
| rdm | 202210 |
| fp16 | 202210 |
| dit | 202210 |
| dpb | 202210 |
| dpb2 | 202210 |
| jscvt | 202210 |
| fcma | 202210 |
| frintts | 202210 |
| sve | 202210 |
| sve2 | 202210 |
| sme | 202210 |
| sb | 202210 |
| ssbs | 202210 |
| bti | 202210 |
| crc | **202240** |
| sha2 | 202240 |
| fp | 202240 |
| simd | 202240 |
| sm4 | 202240 |
| sha3 | 202240 |
| fp16fml | 202240 |
| rcpc | 202240 |
| rcpc2 | 202240 |
| i8mm | 202240 |
| bf16 | 202240 |
| f32mm | 202240 |
| f64mm | 202240 |
| sve2-aes | 202240 |
| sve2-bitperm | 202240 |
| sve2-sha3 | 202240 |
| sve2-sm4 | 202240 |
| memtag | 202240 |
| wfxt | 202240 |
| sme2 | 202240 |
| rcpc3 | **202320** |
| sme-f64f64 | 202320 |
| sme-i16i64 | 202320 |
| rdma | **202410** |
| mops | 202410 |
| cssc | **202520** |

### Dependencies

If a feature depends on another feature as defined by the following table then:
Expand Down
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