Wrong complier with struct

[Jirat]

I write code as follow.

typedef struct
{
uint8_t data1;
uint8_t data2;
uint8_t data3;
uint16_t data4;
uint16_t data5;
uint16_t data6;
}testStructdef_t;

_pdata testStructdef_t test;

uint16_t convertTest(uint8_t ch)
{
uint16_t data;
data = (uint16_t)
return
}

void initValue(uint8_t ch , testStructdef_t *test)
{

//uint16_t buf;
test->data1 = 4;
test->data2= 5;
test->data3 = 6;
test->data4 = 4;
test->data5 = convertTest(ch);
test->data6 = test->data5 * 16;
}

main()
{
initValue(7,&test)
while(1)
{
}
}

After check listing file we found the problem at this line.
lcall _convertTest
0001BB AF 82 [24] 567 mov r7,dpl
0001BD AB 83 [24] 568 mov r3,dph
0001BF D0 04 [24] 569 pop ar4
0001C1 D0 05 [24] 570 pop ar5
0001C3 D0 06 [24] 571 pop ar6
0001C5 A8 2A [24] 572 mov r0,_bp
0001C7 08 [12] 573 inc r0
0001C8 08 [12] 574 inc r0
0001C9 86 82 [24] 575 mov dpl,@r0
0001CB 08 [12] 576 inc r0
0001CC 86 83 [24] 577 mov dph,@r0
0001CE 08 [12] 578 inc r0
0001CF 86 F0 [24] 579 mov b,@r0
0001D1 EF [12] 580 mov a,r7
0001D2 12 03 DD [24] 581 lcall gptrput
0001D5 A3 [24] 582 inc dptr
0001D6 EB [12] 583 mov a,r3
0001D7 12 03 DD [24] 584 lcall gptrput
585 ; .\src\main.c:84: test->data6 = (uint16_t) (test->data5 * 16);
0001DA 74 07 [12] 586 mov a,#0x07
0001DC 2C [12] 587 add a,r4
0001DD FC [12] 588 mov r4,a
0001DE E4 [12] 589 clr a
0001DF 3D [12] 590 addc a,r5
0001E0 FD [12] 591 mov r5,a
0001E1 8F 03 [24] 592 mov ar3,r7
0001E3 8B 07 [24] 593 mov ar7,r3
0001E5 EF [12] 594 mov a,r7**

[Jirat]

This 2 line are problem .

0001E1 8F 03 [24] 592 mov ar3,r7
0001E3 8B 07 [24] 593 mov ar7,r3

r7 and r3 keep the result from function "convertTest"
and it destroy itself before use to mul with 16.

If I rewrite initValue function to

void initValue( testStructdef_t *test,uint8_t ch )

Just swap the parameter and pass with new order parameter.
then the problem will be solved.
Anyone found this problem before?

[Jirat]

Please note such problem will occur once I enable "--stack-auto" flag.

[Benedikt Freisen]

The first thing that catches my eye is that this function here looks a bit broken:

uint16_t convertTest(uint8_t ch)
{
    uint16_t data;
    data = (uint16_t)
    return
}

Shouldn't that rather be something like the following?

uint16_t convertTest(uint8_t ch)
{
    uint16_t data;
    data = (uint16_t) ch;
    return data;
}

[Jirat]

uint16_t convertTest(uint8_t ch)
{
uint16_t data;
data = (uint16_t) ch;
return data;
}

Yes,you're right, I mistype. But it does not affect anything.
You could write above code by yourself to check it.
Please compile to MCS51 mcu ,you will get the same problem.

[Philipp Klaus Krause]

I can reproduce the issue using the attached regression test with current sdcc on my Debian GNU/Linux testing system on amd64.
It affects the mcs51 port with --stack-auto only; but there I see it for small, medium and large memory model. Other ports with --stack-auto (or ports that put local variables on the stack by default) are apparently not affected.

Please file a bug report.

[Oleg Endo]

This looks like [#3607] to me, which has been fixed.

[Maarten Brock]

Bug filed as [#3554]