[PATCH] zstd: Fix decompression of large window archives on 32-bit platforms

From: Petr Malat
Date: Mon Sep 14 2020 - 02:20:12 EST


It seems some optimization has been removed from the code without removing
the if condition which should activate it only on 64-bit platforms and as
a result the code responsible for decompression with window larger than
8MB was disabled on 32-bit platforms.

Signed-off-by: Petr Malat <oss@xxxxxxxxx>
---
lib/zstd/decompress.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/lib/zstd/decompress.c b/lib/zstd/decompress.c
index db6761ea4deb..509a3b8d51b9 100644
--- a/lib/zstd/decompress.c
+++ b/lib/zstd/decompress.c
@@ -1457,12 +1457,8 @@ static size_t ZSTD_decompressBlock_internal(ZSTD_DCtx *dctx, void *dst, size_t d
ip += litCSize;
srcSize -= litCSize;
}
- if (sizeof(size_t) > 4) /* do not enable prefetching on 32-bits x86, as it's performance detrimental */
- /* likely because of register pressure */
- /* if that's the correct cause, then 32-bits ARM should be affected differently */
- /* it would be good to test this on ARM real hardware, to see if prefetch version improves speed */
- if (dctx->fParams.windowSize > (1 << 23))
- return ZSTD_decompressSequencesLong(dctx, dst, dstCapacity, ip, srcSize);
+ if (dctx->fParams.windowSize > (1 << 23))
+ return ZSTD_decompressSequencesLong(dctx, dst, dstCapacity, ip, srcSize);
return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize);
}

--
2.20.1