Re: [Bug inline-asm/36639] New: pointer referenced in asm statement not regarded as VUSE

[Andrew Pinski <pinskia at gmail dot com>]

This is correct as you are just using the address and not the contents  
itself.  This is how inline-asm is documented to work also.

-- Andrew Pinski

Sent from my iPhone

On Jun 25, 2008, at 19:08, "aoliva at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org 
> wrote:

> This is originally derived from code from Linux, in which the  
> physical address
> of a structure is passed to an asm statement as an integral type,  
> causing the
> initializer of the structure to be optimized away.
>
> int main() { int i = 0x12345678; long j = (long)&i; asm ("# %0" : :  
> "r" (j)); }
>
> int main() { int i = 0x12345678; void *j = &i; asm ("#" : :  
> "p" (j)); }
>
> At the very least in the second case above, the compiler should mark  
> the asm
> statement as a VUSE of i.  Arguably, it should do so in the former  
> case as
> well, like it does for pointers passed to function calls as integral  
> types.
>
>
> --
>           Summary: pointer referenced in asm statement not regarded  
> as VUSE
>           Product: gcc
>           Version: 4.3.1
>            Status: UNCONFIRMED
>          Severity: normal
>          Priority: P3
>         Component: inline-asm
>        AssignedTo: unassigned at gcc dot gnu dot org
>        ReportedBy: aoliva at gcc dot gnu dot org
> GCC build triplet: *-*-*
>  GCC host triplet: *-*-*
> GCC target triplet: *-*-*
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36639