[Bug target/81305] New: [avr] avrtiny uses LDS for SREG in ISR routines which is out of range of LDS.

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81305

            Bug ID: 81305
           Summary: [avr] avrtiny uses LDS for SREG in ISR routines which
                    is out of range of LDS.
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gjl at gcc dot gnu.org
  Target Milestone: ---

This problem occurs with -O0 and -mmcu=avrtiny and "signal" or "interrupt"
functions.

Assembler messages:
foo.s:331: Warning: operand out of range: 0x3f

ISR prologue start reads:

__vector_1:
        push r17
        push r16
        lds r16,63  ;; BUG
        push r16
        ...

Fix is to use IN no matter whether optimization is on.