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Build: Fix ARM64 CRC32 instruction feature test.

Old versions of Clang reported the unsupported function attribute and
__crc32d() function as warnings instead of errors, so the feature test
passed when it shouldn't have, causing a compile error at build time.
-Werror was added to this feature test to fix this. The change is not
needed for CMake because check_c_source_compiles() also performs
linking and the error is caught then.

Thanks to Sebastian Andrzej Siewior for reporting this.
This commit is contained in:
Jia Tan 2024-02-23 16:12:32 +08:00
parent 4c81c9611f
commit 32b0a3ce19

View file

@ -1104,6 +1104,14 @@ AC_MSG_CHECKING([if ARM64 CRC32 instruction is usable])
AS_IF([test "x$enable_arm64_crc32" = xno], [ AS_IF([test "x$enable_arm64_crc32" = xno], [
AC_MSG_RESULT([no, --disable-arm64-crc32 was used]) AC_MSG_RESULT([no, --disable-arm64-crc32 was used])
], [ ], [
# Set -Werror here because some versions of Clang (14 and older)
# do not report the unsupported __attribute__((__target__("+crc")))
# or __crc32d() as an error, only as a warning. This does not need
# to be done with CMake because tests will attempt to link and the
# error will be reported then.
OLD_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS -Werror"
AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
#include <arm_acle.h> #include <arm_acle.h>
#include <stdint.h> #include <stdint.h>
@ -1124,6 +1132,8 @@ uint32_t my_crc(uint32_t a, uint64_t b)
enable_arm64_crc32=no enable_arm64_crc32=no
]) ])
AC_MSG_RESULT([$enable_arm64_crc32]) AC_MSG_RESULT([$enable_arm64_crc32])
CFLAGS="$OLD_CFLAGS"
]) ])
# Check for ARM64 CRC32 instruction runtime detection. # Check for ARM64 CRC32 instruction runtime detection.