On 2021-08-25, Daniel Kiper wrote:
>On Mon, Aug 23, 2021 at 11:18:38PM -0700, Fangrui Song wrote:
>> Clang does not support -falign-jumps and only recently gained support
>> for -falign-loops. Test all the alignment options to avoid passing
>> unrecognized options to Clang:
>>
>>     clang-14: error: optimization flag '-falign-jumps=1' is not supported [-Werror,-Wignored-optimization-argument]
>>
>> When compiled with older Clang, the alignment options are not added, so
>> just avoid the complexity for each option.
>>
>> Signed-off-by: Fangrui Song <maskray@google.com>
>> ---
>>  configure.ac | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/configure.ac b/configure.ac
>> index 9a12151bd..8625e6776 100644
>> --- a/configure.ac
>> +++ b/configure.ac
>> @@ -798,8 +798,9 @@ fi
>>
>>  # Force no alignment to save space on i386.
>>  if test "x$target_cpu" = xi386; then
>> -  AC_CACHE_CHECK([whether -falign-loops works], [grub_cv_cc_falign_loop], [
>> -    CFLAGS="$TARGET_CFLAGS -falign-loops=1 -Werror"
>> +  AC_CACHE_CHECK([whether -falign-jumps=1 -falign-loops=1 -falign-functions=1 works],
>> +    [grub_cv_cc_falign_loop], [
>> +    CFLAGS="$TARGET_CFLAGS -falign-jumps=1 -falign-loops=1 -falign-functions=1 -Werror"
>
>I would prefer if you add a separate check for every -falign-* option.
>
>Daniel

The attached patch checks both -falign-jumps=1 and -falign-loops=1