#3379 stm8 regression, bool function parameters

[Martin Kaiser]

Hi all,

first and foremost: thanks for providing and maintaining sdcc.
I've been using the stm8 port for a while and it works great.

After upgrading to sdcc 4.2, I noticed the following problem, though:

#define __PB_ODR *(volatile unsigned char *)0x5005                              

static inline void toggle_a_gpio(void)                                          
{                                                                               
    __PB_ODR |= 0x1;                                                            
}                                                                               

static void sub_func(bool my_sub_flag)                                          
{                                                                               
    printf("%s(): my_sub_flag %d\n", __func__, my_sub_flag);                    
}                                                                               

static void sdcc42_bug(bool my_flag)                                            
{                                                                               
    printf("%s(): my_flag %d\n", __func__, my_flag);                            

    if (my_flag)                                                                
        toggle_a_gpio();                                                        
    else                                                                        
        toggle_a_gpio();                                                        

    sub_func(true);                                                             
}                                                                               

The output of sdcc42_bug(false) with sdcc 4.1 is, not surprisingly:

sdcc42_bug(): my_flag 0
sub_func(): my_sub_flag 1

But sdcc 4.2 seems to relay the my_flag parameter to sub_func. The output of sdcc42_bug(false) is

sdcc42_bug(): my_flag 0
sub_func(): my_sub_flag 0

I played around with this. Triggering the bug requires and if-else statement (no else -> no bug) and a function call in if and else. Of course, my original code called two different functions. Calling printf("blabla\n") instead of toggle_a_gpio does not trigger the bug.

sdcc 4.1 generates this assembler code

                                    790 ;       main.c: 107: sub_func(true);
      000233 4B 01            [ 1]  791         push    #0x01
      000235 CDr01rFD         [ 4]  792         call    _sub_func
      000238 84               [ 1]  793         pop     a
                                    794 ;       main.c: 108: }

and sdcc 4.2 generates

      00021D                        771 00103$:
                                    772 ;       main.c: 107: sub_func(true);
      00021D A6 01            [ 1]  773         ld      a, #0x01
      00021F 84               [ 1]  774         pop     a
      000220 CCr01rE6         [ 2]  775         jp      _sub_func
                                    776 ;       main.c: 108: }

Shouldn't this be push a to store the parameter on the stack for sub_func to pick it up?

Needless to say, I'm happy to provide further infos or to do some more testing with my setup.

Thanks,
Martin

[Philipp Klaus Krause]

I can reproduce the issue on my Debian GNU/Linux testing system using SDCC 4.2.2 #13377.

[Philipp Klaus Krause]

Fixed in [r13380].