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Couple tweaks to improve decompression speed with clang PGO compilation #3576

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Merged
merged 2 commits into from
Mar 31, 2023
Merged

Couple tweaks to improve decompression speed with clang PGO compilation #3576

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e6dccbf
Inline BIT_reloadDStream
zhuhan0 Mar 27, 2023
b558190
Remove clang-only branch hints from ZSTD_decodeSequence
zhuhan0 Mar 28, 2023
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2 changes: 1 addition & 1 deletion lib/common/bitstream.h
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Original file line number Diff line number Diff line change
Expand Up @@ -396,7 +396,7 @@ MEM_STATIC BIT_DStream_status BIT_reloadDStreamFast(BIT_DStream_t* bitD)
* This function is safe, it guarantees it will not read beyond src buffer.
* @return : status of `BIT_DStream_t` internal register.
* when status == BIT_DStream_unfinished, internal register is filled with at least 25 or 57 bits */
MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD)
MEM_STATIC FORCE_INLINE_ATTR BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD)
{
if (bitD->bitsConsumed > (sizeof(bitD->bitContainer)*8)) /* overflow detected, like end of stream */
return BIT_DStream_overflow;
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12 changes: 0 additions & 12 deletions lib/decompress/zstd_decompress_block.c
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Expand Up @@ -1232,11 +1232,7 @@ ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets)

/* sequence */
{ size_t offset;
#if defined(__clang__)
if (LIKELY(ofBits > 1)) {
#else
if (ofBits > 1) {
#endif
ZSTD_STATIC_ASSERT(ZSTD_lo_isLongOffset == 1);
ZSTD_STATIC_ASSERT(LONG_OFFSETS_MAX_EXTRA_BITS_32 == 5);
ZSTD_STATIC_ASSERT(STREAM_ACCUMULATOR_MIN_32 > LONG_OFFSETS_MAX_EXTRA_BITS_32);
Expand Down Expand Up @@ -1273,11 +1269,7 @@ ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets)
seq.offset = offset;
}

#if defined(__clang__)
if (UNLIKELY(mlBits > 0))
#else
if (mlBits > 0)
#endif
seq.matchLength += BIT_readBitsFast(&seqState->DStream, mlBits/*>0*/);

if (MEM_32bits() && (mlBits+llBits >= STREAM_ACCUMULATOR_MIN_32-LONG_OFFSETS_MAX_EXTRA_BITS_32))
Expand All @@ -1287,11 +1279,7 @@ ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets)
/* Ensure there are enough bits to read the rest of data in 64-bit mode. */
ZSTD_STATIC_ASSERT(16+LLFSELog+MLFSELog+OffFSELog < STREAM_ACCUMULATOR_MIN_64);

#if defined(__clang__)
if (UNLIKELY(llBits > 0))
#else
if (llBits > 0)
#endif
seq.litLength += BIT_readBitsFast(&seqState->DStream, llBits/*>0*/);

if (MEM_32bits())
Expand Down