[tree-ssa] tree-ssa vs. fold

[Jason Merrill]

On Sat, 28 Jun 2003 20:55:25 -0400 (EDT), Jeff Sturm <jsturm@one-point.com> wrote:

> On Sat, 28 Jun 2003, Jason Merrill wrote:
>> How about checking TREE_SIDE_EFFECTS instead of looking for SSA_NAME?
>
> If we can be confident that TREE_SIDE_EFFECTS == TREE_THIS_VOLATILE for
> GIMPLE binop nodes

A GIMPLE binop node can never have side effects; as of my recent change to
is_gimple_val, a volatile decl will be copied into a temporary.

> 	* fold-const.c (fold): Don't save_expr unless TREE_SIDE_EFFECTS.

OK.

> 	* tree-ssa.c (rewrite_and_optimize_stmt): Check has_volatile_ops
> 	before folding.

I don't think this is necessary anymore.

Jason