Wouter, that's it. I always tried the simplified examples using arrays of the
same size.
The following:
#include <stdint.h>
volatile uint8_t b;
int main (void) {
while(1) {
{
uint8_t a1[200];
b = a1[b];
}
{
uint8_t a2[210];
b = a2[b];
}
}
}
(The read to volatile uint8_t b is to prevent the optimiser to get rid of the
arrays altogether).
As a1[] and a2[] have limited scope/life in non-overlapping blocks, they may
and should use the same stack space.
However
11 main:
12 0000 DF93 push r29
13 0002 CF93 push r28
14 0004 CDB7 in r28,__SP_L__
15 0006 DEB7 in r29,__SP_H__
16 0008 CA59 subi r28,lo8(-(-410))
17 000a D140 sbci r29,hi8(-(-410))
i.e. stack frame of 200 + 210 bytes is used.
The inlined functions are only a variation of this problem.
Still I wouldn't call this a bug, but that's just terminology. Let's just call
it a serious case of missed optimisation... :-)
Jan Waclawek
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