diff --git a/lib/decompress/zstd_decompress_block.c b/lib/decompress/zstd_decompress_block.c index 7c046dab5..466e83b6b 100644 --- a/lib/decompress/zstd_decompress_block.c +++ b/lib/decompress/zstd_decompress_block.c @@ -1170,9 +1170,27 @@ FORCE_INLINE_TEMPLATE seq_t ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets) { seq_t seq; + /* + * ZSTD_seqSymbol is a structure with a total of 64 bits wide. So it can be + * loaded in one operation and extracted its fields by simply shifting or + * bit-extracting on aarch64. + * GCC doesn't recognize this and generates more unnecessary ldr/ldrb/ldrh + * operations that cause performance drop. This can be avoided by using this + * ZSTD_memcpy hack. + */ +#if defined(__aarch64__) && (defined(__GNUC__) && !defined(__clang__)) + ZSTD_seqSymbol llDInfoS, mlDInfoS, ofDInfoS; + ZSTD_seqSymbol* const llDInfo = &llDInfoS; + ZSTD_seqSymbol* const mlDInfo = &mlDInfoS; + ZSTD_seqSymbol* const ofDInfo = &ofDInfoS; + ZSTD_memcpy(llDInfo, seqState->stateLL.table + seqState->stateLL.state, sizeof(ZSTD_seqSymbol)); + ZSTD_memcpy(mlDInfo, seqState->stateML.table + seqState->stateML.state, sizeof(ZSTD_seqSymbol)); + ZSTD_memcpy(ofDInfo, seqState->stateOffb.table + seqState->stateOffb.state, sizeof(ZSTD_seqSymbol)); +#else const ZSTD_seqSymbol* const llDInfo = seqState->stateLL.table + seqState->stateLL.state; const ZSTD_seqSymbol* const mlDInfo = seqState->stateML.table + seqState->stateML.state; const ZSTD_seqSymbol* const ofDInfo = seqState->stateOffb.table + seqState->stateOffb.state; +#endif seq.matchLength = mlDInfo->baseValue; seq.litLength = llDInfo->baseValue; { U32 const ofBase = ofDInfo->baseValue;