[Bug c/100491] Code generation get worse when including function prototype on ARM

[fredrik.hederstierna@securitas-direct.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100491

--- Comment #1 from Fredrik Hederstierna <fredrik.hederstierna@securitas-direct.com> ---
Created attachment 50780
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50780&action=edit
makefile

Adding makefile to compile test example. See in makefile how to
trigger/untrigger the unexpected condition.