llvm dev - May 2011 - [LLVMdev] which pass for optimizing access to a global struct?

Hi!

which pass do you recommend to optimize access to a global
struct? for example:

struct
{
int a;
int b;
} global;

void foo(int x)
{
     global.a = x;
     int y = global.a; // should be replaced by int y = x;
}

I guess it's one of the alias passes but which one to choose?
Thanks,
-Jochen

Hi Jochen,
> which pass do you recommend to optimize access to a global
> struct? for example:
>
> struct
> {
> int a;
> int b;
> } global;
>
> void foo(int x)
> {
>       global.a = x;
>       int y = global.a; // should be replaced by int y = x;
> }
the global value numbering (gvn) pass can do this, as can the instruction
combiner (-instcombine).  Maybe there are some others too.

Ciao, Duncan.
>
> I guess it's one of the alias passes but which one to choose?
> Thanks,
> -Jochen
>
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