[Bug c/49016] always_inline causes references below the current stack pointer

[merrill_707_1 at yahoo dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49016

--- Comment #7 from Lee Merrill <merrill_707_1 at yahoo dot com> 2011-05-17 13:42:23 UTC ---
I think what is happening in the compiler BTW is that a "sub $XX, %rsp" is
dropping out, perhaps as an optimization. If for example, you comment out the
"#define inline" line in the test code, a stack adjustment appears:

   0:   55                      push   %rbp
   1:   48 89 e5                mov    %rsp,%rbp
   4:   48 83 ec 10             sub    $0x10,%rsp       # SP adjustment here
   8:   48 89 7d f8             mov    %rdi,-0x8(%rbp)
   c:   89 75 f4                mov    %esi,-0xc(%rbp)
etc.

And as far as using stack space below your stack pointer, suppose someone has
an operating system that runs applications at the same privilege level as the
OS?