[PATCH] x86: Change -malign-branch= to accept a comma separated list

[Fangrui Song via binutils]

On 2020-01-16, H.J. Lu wrote:
>On Thu, Jan 16, 2020 at 8:49 PM Fangrui Song via binutils
><binutils@sourceware.org> wrote:
>>
>> It is a convention to use a comma separated list.
>>
>> -fsanitize=address,undefined
>> -fsanitize=null,alignment
>> -fpatchable-function-entry=3,1
>> -finstrument-functions-exclude-function-list=a,b
>> -mrecip=all,!sqrt
>> -mfpmath=sse,387
>
>  -malign-branch=TYPE[+TYPE...] (default: jcc+fused+jmp)
>
>is done on purpose since you can't pass comma in assembler options
>from GCC driver to assembler with -Wa,....

Thanks for explaining the motivation.

We can make -malign-branch= both an assembler option and a compiler
driver option (https://gcc.gnu.org/ml/gcc/2020-01/msg00315.html)

Then we can let gcc pass -malign-branch=jcc,jmp to gas.