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Do not opt into sse4.2 for arm64 CPUs in crc32 library

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The fork of the crc32 library in contrib makes use of streaming SIMD
instructions where possible. This is achieved via a preprocessor directive, but
short-circuiting of the evaluation previously meant that any use of clang or
GCC opted into SSE regardless.

This commit adds additional parentheses to ensure a warning-free build of the
CRC32 library using clang on ARM64 machines.

On macOS on Apple Silicon:

```
$ uname -m
arm64
```

Before:

```
$ ninja crc32
[0/2] Re-checking globbed directories...
[3/4] Building CXX object contrib/crc32/CMakeFiles/crc32.dir/crc32c.cpp.o
'+sse4.2' is not a recognized feature for this target (ignoring feature)
'+sse4.2' is not a recognized feature for this target (ignoring feature)
[4/4] Linking CXX static library lib/libcrc32.a
```

After:

```
$ ninja -t clean
Cleaning... 5 files.

$ ninja crc32
[0/2] Re-checking globbed directories...
[4/4] Linking CXX static library lib/libcrc32.a
```
This commit is contained in:
James Nugent 2024-01-11 19:32:30 -06:00
parent 947dc32963
commit 3813e08129
1 changed files with 1 additions and 1 deletions
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2
contrib/crc32/crc32c.cpp
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@ -178,7 +178,7 @@ static inline uint32_t shift_crc(uint32_t shift_table[][256], uint32_t crc) {
}
/* Compute CRC-32C using the hardware instruction. */
#if (defined(__clang__) || defined(__GNUG__) && !defined(__aarch64__) && !defined(__powerpc64__))
#if ((defined(__clang__) || defined(__GNUG__)) && !defined(__aarch64__) && !defined(__powerpc64__))
/* Enable SSE CEC instructions on Intel processor */
__attribute__((target("sse4.2")))
#endif