ggml-hexagon: add F16 support for unary ops (#28228)
Extend the HTP backend's F16 unary op coverage to include ABS on top
of the existing NORM/RMS_NORM/L2_NORM/SCALE/CLAMP/SQR/SQRT set.
- Add hvx_abs_f16_{aa,au,ua,uu} + dispatcher in hvx-arith.h, mirroring
the sqr_f16 kernel structure and using the existing hvx_vec_abs_f16()
sign-bit-clear helper
- Add abs_f16() row-wise dispatch and DEFINE_UNARY_TASK_F16(unary_abs, ...)
in unary-ops.c, wired into execute_op_unary()'s op_type/task_func
switches
- Register HTP_OP_UNARY_ABS in htp_op_is_unary() (unary-ops.h) so that
ggml_hexagon_precompute_unary_params() fills kernel_params (n_threads,
VTCM layout) for ABS nodes -- required for the F16 path to function
- Narrow the F16 GGML_OP_UNARY gate in ggml_hexagon_supported_unary()
(ggml-hexagon.cpp) to allow GGML_UNARY_OP_ABS specifically, instead of
rejecting all GGML_OP_UNARY ops for F16
- Merge the separate execute_op_unary_f32()/execute_op_unary_f16()
functions into a single execute_op_unary(), branching on an is_f16
flag for the parts that actually differ by type (elem_size, the
early F16 op-support check, and which task_func table to use) while
keeping the F32-only tiled/RMS_NORM_MUL paths intact -- per review
feedback to avoid duplicating the shared VTCM/DMA plumbing
Verified on-device (QRD8850, Hexagon v81) via test-backend-ops -o ABS:
8/8 passing (F16 + F32, HTP0, no CPU fallback). Regression-checked
SQR/CLAMP/SQRT (F16+F32) and NORM/RMS_NORM/L2_NORM/SCALE (F32; their F16
paths have no CPU reference kernel in test-backend-ops and cannot be
correctness-tested there independent of this change).
