[Bug ipa/113293] Incorrect code after inlining function containing extended asm

[amonakov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113293

Alexander Monakov <amonakov at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |amonakov at gcc dot gnu.org

--- Comment #3 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
(In reply to KBDeveloper from comment #2)
> 
> Ah, that makes sense. I had assumed that taking the address of arg would
> force gcc to store it in memory somewhere. 
> Is there a reason why gcc then allocates 8 bytes on the stack and fills r1
> with sp - #7? Or is what I had just UB and gcc can do whatever?

The compiler allocates stack memory for 'arg' and passes the address of 'arg'
to the asm; it is necessary in case the asm does something with it without
reading 'arg' itself. One example would be installing a hardware watchpoint on
that memory location.