Mark,
it occurred to me that asking the question you pose may use language that is
more unfamiliar than necessary. How about this question instead -- assume
struct S { int s; };
struct X {
int i;
struct S s;
};
void g(struct S*);
void f() {
X x;
g(&x.s);
}
Would the compiler be allowed to realize that X::i is never referenced and
therefore a dead variable? I assume the compiler doesn't do that right now,
but it would be straightforward for a scalar replacement algorithm to not
even allocate stack space for X::i, but only X::s, and hand the address of
the only remaining stack object, of type S, to g().
The community at large may have more experience with such "as-if" related
questions. It would be interested to know whether the scalarizers in gcc
realize, for example, whether they can/can't get rid of X::i...
Best
Wolfgang
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Wolfgang Bangerth email: [EMAIL PROTECTED]
www: http://www.ices.utexas.edu/~bangerth/
