On 02/29/12 03:22, Richard Guenther wrote:
So fixing up individual passes is easier - I can only think of PRE being
problematic right now, I am not aware that any other pass moves loads
or stores. So I'd simply pre-compute the stmt bit in PRE and adjust
the
if (gimple_has_volatile_ops (stmt)
|| stmt_could_throw_p (stmt))
continue;
in compute_avail accordingly.
Initially I thought PRE would be problematic for transactions, but
perhaps it isn't. As I understand, for PRE we hoist loads/computations
that are mostly redundant, but will be performed on every path:
if (flag)
a = b + c;
else
stuff;
d = b + c; <-- [b + c] always computed
Even if we hoist [b + c] before the flag, [b + c] will be computed on
every path out of "if (flag)...". So... we can allow this
transformation within transactions, right?
Torvald?
