Comment 6 for bug 1698217

The one I tested was the latest one on the launchpad page: https://launchpad.net/gcc-arm-embedded
I assume you mean this one: https://developer.arm.com/open-source/gnu-toolchain/gnu-rm/downloads

Which doesn't run on my work Linux system because of the glibc version. It does work on Windows and the stack seems to be set right. It still has the quirky "optimization" with r7:

Dump of assembler code for function FunctionA:
   0x00008130 <+0>: push {r4, r7, lr}
   0x00008132 <+2>: sub sp, #12
   0x00008134 <+4>: add r7, sp, #0
   0x00008136 <+6>: movs r1, #4
   0x00008138 <+8>: adds r0, r7, #4
   0x0000813a <+10>: mov r4, sp
   0x0000813c <+12>: bl 0x8170 <FunctionC>