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Arm SVE: Add merge versions of CreateBreak APIs #117722
Description
Background and motivation
Currently we have (approved in #98184)
/// <summary>
/// <para>svbool_t svbrka[_b]_z(svbool_t pg, svbool_t op)</para>
/// <para> BRKA Presult.B, Pg/Z, Pop.B</para>
/// </summary>
public static Vector<byte> CreateBreakAfterMask(Vector<byte> totalMask, Vector<byte> fromMask);This uses the zeroing version of the instruction. ie: every lane in totalMask that is empty will be zeroed in the result.
If the user wanted to use the merging version, then they could do:
x = Sve.ConditionalSelect(mask, Sve.CreateBreakAfterMask(mask, op1), op1);Alternatively, we could add new APIs.
For background see #104486 and #104184 (comment)
API Proposal
/// T: sbyte, short, int, long, byte, ushort, uint, ulong
public static unsafe Vector<T> CreateBreakAfterMaskMerging(Vector<T> mask, Vector<T> from); // BRKA // predicated
/// T: sbyte, short, int, long, byte, ushort, uint, ulong
public static unsafe Vector<T> CreateBreakAfterPropagateMaskMerging(Vector<T> mask, Vector<T> left, Vector<T> right); // BRKPA
/// T: sbyte, short, int, long, byte, ushort, uint, ulong
public static unsafe Vector<T> CreateBreakBeforeMaskMerging(Vector<T> mask, Vector<T> from); // BRKB // predicated
/// T: sbyte, short, int, long, byte, ushort, uint, ulong
public static unsafe Vector<T> CreateBreakBeforePropagateMaskMerging(Vector<T> mask, Vector<T> left, Vector<T> right); // BRKPBThese are identical to the existing CreateBreak APIs, except that they use the merge variants.
Activity
dotnet-policy-service commentedon Jul 16, 2025
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