[PATCH] as: fix bpf expression parsing regression

[Jose E. Marchesi]

>>> diff --git a/gas/testsuite/gas/bpf/indcall-badoperand.l b/gas/testsuite/gas/bpf/indcall-badoperand.l
>>> new file mode 100644
>>> index 00000000000..d791435a2ac
>>> --- /dev/null
>>> +++ b/gas/testsuite/gas/bpf/indcall-badoperand.l
>>> @@ -0,0 +1,3 @@
>>> +.*: Assembler messages:
>>> +.*:7: Error: unrecognized instruction `call %0'
>>> +.*:7: Error: expected register name, got '%0'
>>> diff --git a/gas/testsuite/gas/bpf/indcall-badoperand.s b/gas/testsuite/gas/bpf/indcall-badoperand.s
>>> new file mode 100644
>>> index 00000000000..cf19c0a56b6
>>> --- /dev/null
>>> +++ b/gas/testsuite/gas/bpf/indcall-badoperand.s
>>> @@ -0,0 +1,8 @@
>>> +
>>> +    .text
>>> +    .align 4
>>> +main:
>>> +
>>> +    mov %r0, 1
>>> +    call %0
>>
>> What is this test supposed to test exactly?
>
> Never mind, now that I reread your mail it is pretty obvious.
>
> I tried your patch, and I am getting some non-deterministic behavior.
> Assembling indcall-badoperand.s the assembler sometimes emits:
>
>   foo.s: Assembler messages:
>   foo.s:7: Error: unrecognized instruction `call %0'
>   foo.s:7: Error: expected signed 32-bit displacement
>
> and sometimes it emits:
>
>   foo.s: Assembler messages:
>   foo.s:7: Error: unrecognized instruction `call %0'
>   foo.s:7: Error: expected register name, got '%0'
>
> Running under valgrind seems to settle on this latest, and expected,
> output, so this seems to be a memory problem.  I will apply your patch
> (on your behalf) only after I find and fix this other bug, or the
> buildbots will go banana.

Hi Will.

Found the cause and fixed it [1] then applied your patch on your behalf,
with a slightly modified ChangeLog.

Thank you!

[1] b86b514aace19799ea141514e16296fb63a089b3