mirror of https://chromium.googlesource.com/libyuv/libyuv synced 2026-10-29 02:17:13 +08:00

Frank Barchard 149568401f SVE2 row functions needed for multipass image functions

- MergeUVRow_SVE2: Interleaves U and V
 - SplitUVRow_SVE2: De-interleaves UV
 - InterpolateRow_SVE2: Bilinear row interpolation
 - YUY2ToYRow_SVE2, YUY2ToUVRow_SVE2, UYVYToYRow_SVE2, UYVYToUVRow_SVE2
 - HalfMergeUVRow_SVE2: 2:1 vertical averaging of U and V

OnePlus 15 with Qualcomm Snapdragon 8 Elite Gen 5 Oryon V3

Benchmark (1280x720 1000x)     | SVE2   | NEON   | Result
-------------------------------+--------+--------+------------------
TestInterpolatePlane           | 119 ms | 164 ms | SVE2 is 1.38x win
TestInterpolatePlane_16        | 138 ms | 172 ms | SVE2 is 1.25x win
SplitUVPlane_Opt               |  68 ms |  69 ms | SVE2 is 1.01x win
MergeUVPlane_Opt               |  40 ms |  40 ms | Tied
SwapUVPlane_Opt                |  72 ms |  72 ms | Tied
HalfMergeUVPlane_Opt           |  50 ms |  50 ms | Tied
I420ToNV12_Opt                 |  25 ms |  26 ms | SVE2 is faster
I420ToNV21_Opt                 |  26 ms |  26 ms | Tied
YUY2ToNV12_Opt                 |  79 ms |  81 ms | SVE2 is faster
NV21ToNV12_Opt                 |  36 ms |  35 ms | Tied
Android420ToI420ToNV12_Opt     |  53 ms |  53 ms | Tied
Android420ToI420ToNV21_Opt     |  35 ms |  33 ms | NEON is faster
YUY2ToI420_Opt                 |  87 ms |  84 ms | NEON is faster
UYVYToI420_Opt                 |  87 ms |  83 ms | NEON is faster
YUY2ToI422_Opt                 | 101 ms |  97 ms | NEON is faster
UYVYToI422_Opt                 | 101 ms |  97 ms | NEON is faster
UYVYToNV12_Opt                 | 111 ms | 108 ms | NEON is faster
ARGBToNV21_Opt                 | 279 ms | 279 ms | Tied
ABGRToNV21_Opt                 | 279 ms | 280 ms | SVE2 is faster
ARGBToNV12_Opt                 | 285 ms | 280 ms | NEON is faster
ABGRToNV12_Opt                 | 284 ms | 281 ms | NEON is faster

Bug: 42280902
Change-Id: I53f633fe453f2853f7bc9fe17280e938912c4e8f
Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/8196068
Reviewed-by: Justin Green <greenjustin@google.com>
Commit-Queue: Frank Barchard <fbarchard@google.com>

2026-08-06 12:40:26 -07:00

2.7 KiB

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Gemini Project Context: libyuv Row Functions

This file provides context for the core row-processing architecture of libyuv. Use these guidelines when refactoring, reviewing, or generating code within the row_*.cc files.

Architectural Overview

Libyuv uses a dispatch system where high-level conversion functions call optimized "Row" functions. These functions are categorized by SIMD architecture and compiler compatibility.

Source File Map

x86 Architectures (32-bit and 64-bit)

row_gcc.cc: Master copy. Contains inline assembly in GCC syntax for GCC and Clang. Supports AVX, and AVX512. AVX512 implementations are strictly for 64-bit targets.
row_win.cc: Derivative of row_gcc.cc. Contains C++ intrinsics specifically for Visual C++ (MSVC). Can be tested with Clang using -DLIBYUV_ENABLE_ROWWIN.
Note: Use either row_gcc or row_win, never both.

ARM Architectures

row_neon.cc: 32-bit ARM. Written entirely in inline assembly for GCC/Clang.
row_neon64.cc: 64-bit ARM (AArch64). Written entirely in inline assembly for GCC/Clang.
row_sve.cc: ARMv9 Scalable Vector Extensions (SVE).
row_sme.cc: ARMv9 Scalable Matrix Extension (SME) and Streaming SVE (SSVE).

Other Architectures

row_rvv.cc: RISC-V Vector (RVV). Implemented using intrinsics. Optimized for SiFive X280.
row_lsx.cc / row_lasx.cc: Loongarch MIPS-like extensions.

Utility and Fallbacks

row_common.cc: Portable C/C++ versions. This is the reference implementation.
row_any.cc: Handles "remainder" pixels for widths not multiples of SIMD register size. Used for x86, NEON, and MIPS. Not required for SVE, SME, or RVV due to hardware-level masking.

Coding Guidelines

AVX512 Logic: AVX512 row functions are strictly enabled for 64-bit x86 only.
Feature Macros: Use the HAS_ macros in include/libyuv/row.h to enable or disable specific AVX512 versions.
MSVC Intrinsics (row_win.cc): When converting row_gcc.cc to row_win.cc, use _mm512_permutex2var_epi8, not _mm512_permi2var_epi8 intrinsic.

Changelist (CL) Format Guidelines

When adding new code, remove trailing spaces. When generating descriptions, follow the Chromium standard format. Wrap commit message text at 72 characters

Changelist (CL) Description Example

libyuv] Optimized ARGBToRGB24 for AVX2

Detailed technical explanation of the change. Describe the SIMD
optimization logic and any platform-specific constraints. Mention
if this impacts specific row files like row_gcc.cc.

Test: libyuv_unittest --gunit_filter=*ARGBToRGB24*
Bug: libyuv:12345, b/67890

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