We got a report from the linux-arm-kernel folks about getting spurious
warnings when building the kernel with binutils 2.29. See
https://www.spinics.net/lists/arm-kernel/msg599929.html
which boils down to this testcase.
$> cat /tmp/tst.s
lr .req x30
/tmp/tst.s: Assembler messages:
/tmp/tst.s:1: Warning: ignoring attempt to redefine built-in register 'lr'
Instead let's treat this as a proper alias at startup time thus
avoiding the problem and treating these as proper aliases
rather than new registers. This means that attempts to redefine
the alias with the same "name" will provoke no warning and attempts
to redefine the alias to something else will provoke the above mentioned
warning.
Tested make check-gas and no regressions.
Ok to apply to trunk (and backport to 2.29 branch)?
Regards
Ramana
8975f86409