[Bug target/107032] ARM: libgcc2.c:2174:1: error: r7 cannot be used in 'asm' here

[rearnsha at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107032

Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-09-27
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #6 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
In Thumb code r7 is the frame pointer, so can't be used in inline assembler
without a dance whenever the frame pointer might be needed.  I'm surprised this
hasn't shown up before.

We're going to need a separate definition of this macro when compiling for
Thumb as you can't easily rewrite this.  The code will need to do something
like

mov scratch, r7
mov r7, #<syscall-value>
svc 0
mov r7, scratch