[LLVMdev] x86 Frame Pointer with AVX

[Eric Christopher]

> In trunk, the frame pointer is always set up when an AVX register is used in
> a function. This is done in case 32-byte spill code is later introduced into
> the function and hence dynamic stack realignment is needed. Needless to say,
> it's a big hammer. This regression seems particularly painful in
> small-to-medium sized routines that are called frequently in some codes.
>
>
> Is this issue already known? Is there a plan to fix this regression? If not,
> does anyone have a suggestion on the best way to remedy this issue?
>

You'd need to change the default stack alignment of the platform to
deal with it effectively.

-eric