A function stops being inline. Any explanation?

Question

I have a code of the following structure:

void foo1(uint32_t *num_failures)
{
   ...
}

void foo2(uint32_t *num_failures)
{
   ...
}

void foo3(uint32_t *num_failures)
{
   ...
}

void test()
{
   uint32_t num_failures = 0;
   foo1(&num_failures);
   foo2(&num_failures);
   foo3(&num_failures);
}

Now, what I did was add the following instruction to foo1():

void foo1(uint32_t *num_failures)
{
   ...
   (*num_failures)++;
}

And suddenly I see that stack size printed from inside foo2() is larger by 36 bytes.

I did an objdump and greped for <symbols>. Yielding the following:

Before the change:

...
00004e08 <test>:

After the change:

...
00004e08 <foo2>:
00005588 <test>:

So I guess the function foo2 stopped being inline.

1. Am I correct?
2. Any explanation why that happened?
3. What happened to foo3() after the change? Did it become inline inside foo2() or inside test()?

Not sure if required: I'm using gcc for arc processor.

Answer 1

After learning some more on the subject, and seeing some lectures by Chandler Caruth, I would say the compiler decides almost indeterministicly where to inline the code. Especially when not givinig it any 'inline' hints, as in my case.