[arm-gnu] How to make gas accept Thumb2 insns on armv6-m ?

[Christophe LYON <christophe.lyon@xxxxxx>]

Hello,

I am trying to make gas accept the following sample code:
	mul     r3, r0, r3
	mul     ip, r2, r1
	umull   r0, r1, r2, r0
	add     ip, ip, r3
	add     r1, r1, ip

for armv6-m.
If I use gas -mthumb -march=armv6-m, I get:
toto.s:4: Error: dest must overlap one source register -- `mul ip,r2,r1'
toto.s:5: Error: selected processor does not support `umull r0,r1,r2,r0'

If I use -march=armv6t2 -mthumb, I get:
toto.s:4: Error: dest must overlap one source register -- `mul ip,r2,r1'

I guess I am missing something obvious, but what?

Thanks,

Christophe.