tcg: Reduce copies for plugin_gen_mem_callbacks

We only need to make copies for loads, when the destination
overlaps the address.  For now, only eliminate the copy for
stores and 128-bit loads.

Rename plugin_prep_mem_callbacks to plugin_maybe_preserve_addr,
returning NULL if no copy is made.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
1 file changed