Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Add FMV feature names priority[ABCDE] #371

Open
wants to merge 2 commits into
base: main
Choose a base branch
from
Open

Add FMV feature names priority[ABCDE] #371

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
4d89c7f
Simplify FMV version selection rules
andrewcarlotti Dec 2, 2024
40be6af
Add FMV feature names priority[ABCDE]
andrewcarlotti Dec 2, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
22 changes: 14 additions & 8 deletions main/acle.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -422,6 +422,8 @@ Armv8.4-A [[ARMARMv84]](#ARMARMv84). Support is added for the Dot Product intrin
* Removed Function Multi Versioning features sve-bf16, sve-ebf16, and sve-i8mm.
* Removed Function Multi Versioning features ebf16, memtag3, and rpres.
* Removed Function Multi Versioning feature dgh.
* Simplified Function Multi Versioning version selection rules.
* Add Function Multi Versioning feature names priority[ABCDE].
* Fixed range of operand `o0` (too small) in AArch64 system register designations.
* Fixed SVE2.1 quadword gather load/scatter store intrinsics.
* Removed unnecessary Zd argument from `svcvtnb_mf8[_f32_x2]_fpm`.
Expand Down Expand Up @@ -2827,6 +2829,11 @@ The following table lists the architectures feature mapping for AArch64
| 570 | `FEAT_SME_I16I64` | sme-i16i64 | ```ID_AA64SMFR0_EL1.I16I64 == 0b1111``` |
| 580 | `FEAT_SME2` | sme2 | ```ID_AA64PFR1_EL1.SMEver >= 0b0001``` |
| 650 | `FEAT_MOPS` | mops | ```ID_AA64ISAR2_EL1.MOPS >= 0b0001``` |
| 9995 | N/A | priorityE | N/A |
| 9996 | N/A | priorityD | N/A |
| 9997 | N/A | priorityC | N/A |
| 9998 | N/A | priorityB | N/A |
| 9999 | N/A | priorityA | N/A |

### Selection

Expand All @@ -2837,14 +2844,13 @@ the selection algorithm is platform dependent, where with platform means
CPU/Vendor/OS as in the target triplet.
2. The selection is permanent for the
lifetime of the process.
3. Only those versions could be considered where all
dependent features are available.

Rules of version selection are in order:

4. Select the most specific version else
5. select the version with the highest priority else
6. `"default"` is selected if no other versions are suitable.
3. Among any two versions, the higher priority version is determined by
identifying the highest priority feature that is specified in exactly one of
the versions, and selecting that version.
4. The selection algorithm must select the highest priority versions whose
dependent features are all available.
5. The feature names priorityA, ..., priorityE can be added to a version to
change the selection order according to the above rules.

## Weak linkage

Expand Down
Loading