M68k gas bug

[Pauli]

I've located a problem in the branch relaxation code for the m68k
target.  A jbra instruction which jumps to the next location through
an intervening ".align 2" directive will genearte an eight bit branch
(not a sixteen bit one) which causes fatal errors later on.

The command line I used to generate the problem is:

$ m68k-elf-as -m5307 z.s -o z.o -v
GNU assembler version 2.11 (m68k-elf) using BFD version 2.11
z.s: Assembler messages:
z.s:4: Error: short branch with zero offset: use :w
z.s:4: Error: invalid byte branch offset
$


This is running on an x86 machine with Red Hat 7.
Gas configured via "../configure --target=m68k-elf"
The problem also occurs if -m68000 is used instead of -m5307 but not
if -m68020 is passed.



The input file (z.s) which exhibits the problem:
----------8<-------------
        jbra .L2
        .align  2
.L2:
        rts
---------->8-------------

Without the ".align 2" things seem to work okay.  Unfortunately, gcc
seems to produce plenty of jbras to the next instruction with an
intermediate ".align 2" directive when no optimisation (-O0) is used).

Gas from binutils-2.10 does *not* exhibit this problem but there does
appear to have been some work done on the brach relaxation code post
this version.


Regards,

Pauli