On 12/13/2016 04:56 PM, Jeff Law wrote:
It's probably wise to ensure the stack pointer keeps proper alignment and such, but that's entirely within the asm itself.
Right. But I still need a way to express that the red zone is clobbered. I just don't see *anything* that would allow me to express that.
No idea what's going on with Andrew's example, I haven't dug into it.
Without optimization, GCC keeps a temporary in the red zone (%rbp is equal to %rsp), and the push/pop pair destroys that:
movq %rax, -8(%rbp) #APP # 6 "t.c" 1 push %rbp; pop %rbp # 0 "" 2 #NO_APP movq -8(%rbp), %rax Florian
