Re: Why use "assign_stack_local" instead of using "assign_stack_temp", both from "function.h"? [relates to the RTL-level if-conversion improvement project]

[Jeff Law <law at redhat dot com>]

On 09/23/2015 02:50 PM, Abe wrote:
> Dear all,
>
> What, if anything, is the reason I should be using "assign_stack_local"
> instead of using "assign_stack_temp",
> both from "function.h"?  The stack slot in question doesn`t need to hold
> its value: it is being used for a scratchpad,
> i.e. garbage data; basically, I just need an address for a
> big-enough-and-aligned-enough slot which I can safely
> corrupt what`s in it.  It should be OK from my code`s POV if another
> part of the compiler causes a scratchpad
> slot to be reused, even if it is reused in the same routine in a single
> execution on the target.
If you're allocating your slot late (past the gimple/rtl border), then 
there isn't a significant difference (ie, no reuse/sharing the slot).

So if you're lazily allocating the slot, it shouldn't really matter 
which you use.



jeff