Can shrink-wrapping ever move prologue past an ASM statement?

[Segher Boessenkool]

On Wed, Jul 08, 2015 at 11:22:34AM -0500, Josh Poimboeuf wrote:
> > Writing the asm with a clobber of the stack pointer causes all stack
> > accesses to go via the frame pointer, which causes pretty horrible
> > code.
> 
> As far as I can tell, most (but not all) kernel stack accesses already
> occur via the frame pointer anyway.  Is that bad?  Can you clarify what
> you mean by horrible code?

If you already have a frame pointer anyway it won't get much worse,
sure :-)

If you don't have one yet you will get one, and a stack frame, and
all that boilerplate.  You don't want to force that if you don't
need it.


Segher