path: root/lib
diff options
authorNathan Chancellor <>2021-10-21 13:23:53 -0700
committerNick Terrell <>2021-11-08 16:55:38 -0800
commit0a8ea235837cc39f27c45689930aa97ae91d5953 (patch)
tree9adda1d269538c257c691e3f6cc40de06db243d2 /lib
parenta99a65cfb92c68c48c761ec5e6383caf63124ce1 (diff)
lib: zstd: Add cast to silence clang's -Wbitwise-instead-of-logical
A new warning in clang warns that there is an instance where boolean expressions are being used with bitwise operators instead of logical ones: lib/zstd/decompress/huf_decompress.c:890:25: warning: use of bitwise '&' with boolean operands [-Wbitwise-instead-of-logical] (BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ zstd does this frequently to help with performance, as logical operators have branches whereas bitwise ones do not. To fix this warning in other cases, the expressions were placed on separate lines with the '&=' operator; however, this particular instance was moved away from that so that it could be surrounded by LIKELY, which is a macro for __builtin_expect(), to help with a performance regression, according to upstream zstd pull #1973. Aside from switching to logical operators, which is likely undesirable in this instance, or disabling the warning outright, the solution is casting one of the expressions to an integer type to make it clear to clang that the author knows what they are doing. Add a cast to U32 to silence the warning. The first U32 cast is to silence an instance of -Wshorten-64-to-32 because __builtin_expect() returns long so it cannot be moved. Link: Link: Reported-by: Nick Desaulniers <> Signed-off-by: Nathan Chancellor <> Signed-off-by: Nick Terrell <>
Diffstat (limited to 'lib')
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/zstd/decompress/huf_decompress.c b/lib/zstd/decompress/huf_decompress.c
index 05570ed5f8be..5105e59ac04a 100644
--- a/lib/zstd/decompress/huf_decompress.c
+++ b/lib/zstd/decompress/huf_decompress.c
@@ -886,7 +886,7 @@ HUF_decompress4X2_usingDTable_internal_body(
HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
- endSignal = (U32)LIKELY(
+ endSignal = (U32)LIKELY((U32)
(BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished)
& (BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished)
& (BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished)