[Bug other/54398] Incorrect ARM assembly when building with -fno-omit-frame-pointer -O2

[ramrad01 at arm dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54398

--- Comment #7 from ramrad01 at arm dot com 2012-09-11 10:44:30 UTC ---
On 09/11/12 07:09, jakub at gcc dot gnu.org wrote:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54398
>
> Jakub Jelinek <jakub at gcc dot gnu.org> changed:
>
>             What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                   CC|                            |jakub at gcc dot gnu.org
>
> --- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-09-11 06:09:13 UTC ---
> cselib.c has for this the various spots that special case
> HARD_FRAME_POINTER_REGNUM (or STACK_POINTER_REGNUM or FRAME_POINTER_REGNUM).
> Please see why that doesn't work in this case.
>

This rings a bell.

Maybe the patch mentioned below needs backporting given Carrot is 
reporting this against the 4.6 branch. What's not clear if this is 
reproducible on anything later though.

http://old.nabble.com/-PATCH--Prevent-cselib-substitution-of-FP,-SP,-SFP-td33080657.html

Full disclaimer that I've not investigated whether the same problem 
occurs on trunk.

HTH,
Ramana