gcc for microcontroller

[Claudio Eterno <eterno dot claudio at gmail dot com>]

Reading this email from <tm_gccmail at mail dot kloo dot net> sent on this
mailing list in(2003):
https://gcc.gnu.org/ml/gcc/2003-03/msg01402.html

I agree with quasi all statements. On the first is written:

o Few or no general-purpose registers

  Many microcontrollers use an accumulator-based architecture, which does
  not work with common register allocation algorithms at all, so you wind
  up emulating general-purpose registers using strange techniques.

  Also, stack-based architectures are difficult to accommodate as well.

  Applies to: 68HC11, 8051, Z80, 6502, PicoJava, x86 FPU, etc.


I've some doubts on this:

"stack-based architectures are difficult to accommodate as well"

Can someone explain better this?
If I remember well the C uses the stack for local variable storage,
does he refer to those architectures which are completely stack
oriented (GPR not present)?

Thank you in advance

Claudio