Question about ssa-form in gcc

[Diego Novillo]

On Fri, Dec 17, 2010 at 06:00, Eugen Wagner <wagner.eugen@googlemail.com> wrote:

> int a;
> a  = 100;
> The variable a is not wrapped into SSA_NAME a_1.

Because 'a' is a "memory variable".  Memory is never rewritten into
SSA form.  To represent memory, we use factored use-def chains (the
VDEF/VUSE notation you see in the dumps).  Look in
http://gcc.gnu.org/wiki/GettingStarted for articles/slides describing
the memory SSA representation and aliasing information.

> I guess it has somethink to do with memory-ssa and alias analysis.
> Could anybody confirm or negate?

Correct.  You are looking at memory SSA information.


Diego.