[tree-ssa] Enhance statement checking & fix minor buglets

[Diego Novillo]

On Mon, 2004-04-05 at 13:40, Richard Henderson wrote:

> I couldn't tell from your message what's breaking.
> 
t.1_3 = &a - 24;
t.2_5 = p_3 + t.1_3;

Since &a - 24 is considered a valid gimple constant, we propagate it
into the use of t.1_3 getting the non-gimple code:

t.2_5 = p_3 + &a - 24;

the tree MINUS_EXPR <PLUS_EXPR, CONST_INT> is not a gimple expression.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14672

The quickest fix right now is to disallow
MINUS_EXPR<ADDR_EXPR,CONST_INT> in is_gimple_min_invariant.  Unless
supporting it in fold_stmt was really trivial.


Diego.