#2997 inline __critical bug

[Konstantin Kim]

It seems that __critical keyword may produce invalid bytecode in some conditions.

command line: sdcc -mmcs51 test.c -o test.ihx
SDCC 4.0.0 #11576 (MINGW64)

volatile int cnt;

inline int cnt_get(void) __critical {
    return cnt; 
}

int cnt0;
void main() {
    cnt0 = cnt;
    for(;;) {
        if ( (cnt_get()-cnt0) >= 1) {
            cnt0++;
        }
    }
}

produce log:

../test.c:11: warning 84: 'auto' variable '__2621440001' may be used before initialization
../test.c:11: warning 84: 'auto' variable '__2621440001' may be used before initialization

cnt fetching was broken as well:

    mov r7,#0x01
    jbc ea,00117$
    mov r7,#0x00
00117$:
;   ../test.c:4: return cnt; 
    mov a,_cnt
    mov a,(_cnt + 1)
;   ../test.c:11: if ( (cnt_get()-cnt0) >= 1) {
    mov a,r7
    rrc a
    mov ea,c

Following code

volatile int cnt;

inline int cnt_get(void) {
    return cnt; 
}

int cnt0;
void main() {
    cnt0 = cnt;
    for(;;) {
        int v;
        __critical { v = cnt_get(); }
        if ( (v-cnt0) >= 1) {
            cnt0++;
        }
    }
}

correspond to expected correct cnt fetching

    mov r7,#0x01
    jbc ea,00117$
    mov r7,#0x00
00117$:
;   ../test.c:5: return cnt; 
    mov r5,_cnt
    mov r6,(_cnt + 1)
;   ../test.c:13: __critical { v = cnt_get(); }
    mov a,r7
    rrc a
    mov ea,c