gcc generates incorrect code with -Os

[Krzysztof Halasa]

Hi,

gcc-4.0.1-4.fc4
gcc-4.0.2-8.fc4 (4.0.2 20051125 (Red Hat 4.0.2-8))
i386

gcc -W -Wall -Os test.c -o test -Werror && ./test
array: 1 2
array: 1 2

gcc -W -Wall -O2 test.c -o test -Werror && ./test
array: 1 2
array: 2 3

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=173764

#include <stdio.h>

void test_it(int *array)
{
	int i;

	for (i = 0; i < 2; i++) {
		int value = array[i];
		if (i != 1000 && i != 1001)
			array[i] = value + 1;
	}
}

int main(void)
{
	int array[2] = {1, 2};

	printf("array: %i %i\n", array[0], array[1]);

	test_it(array);

	printf("array: %i %i\n", array[0], array[1]);

	return 0;
}

-- 
Krzysztof Halasa