| Issue |
143247
|
| Summary |
clang generates incorrect code when storing to memory location 0x1 for target avr-none
|
| Labels |
clang
|
| Assignees |
|
| Reporter |
tomtor
|
sample code:
```
#define PA 0x1 // Bad
//#define PA 0x2 // Good
char *const PORT = (char *const) PA;
extern void nil(short);
void bug()
{
short s= 0;
while (1) {
s++;
*PORT = *PORT | 0x80;
nil((s & 0xF) + 1);
}
}
```
compiled with clang build from git yesterday:
`clang -O2 -target avr-none -mmcu=attiny402 -S bug.c`
generates an incorrect store (uses s which changes in each loop iteration instead of constant 0x1):
```
bug: ; @bug
; %bb.0: ; %entry
push r16
push r17
ldi r26, 0
ldi r27, 0
.LBB0_1: ; %while.cond
; =>This Inner Loop Header: Depth=1
ld r24, X+
ori r24, -128
movw r16, r26
andi r26, 15
andi r27, 0
st X+, r24
movw r24, r26
call nil
movw r26, r16
rjmp .LBB0_1
```
using `#define PA 0x2`
generates correct code:
```
bug: ; @bug
; %bb.0: ; %entry
push r16
push r17
ldi r24, 0
ldi r25, 0
.LBB0_1: ; %while.cond
; =>This Inner Loop Header: Depth=1
sbi 2, 7
adiw r24, 1
movw r16, r24
andi r24, 15
andi r25, 0
adiw r24, 1
call nil
movw r24, r16
rjmp .LBB0_1
```
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