On 02/24/2017 12:07 AM, Alan Modra wrote:
I'm going to wait for Vlad's opinion. I've written a couple of
replies and erased them, since I figure whatever I have to say doesn't
carry much weight.
I would prefer not to touch simplify_subreg_operand, especially a
code related to subreg of mem. Changes of the code usually result in a
long time stabilization work. The change might result in LRA cycling (I
remember it happened before exactly for ppc SD memory handling). It is
dangerous when we are closer to the release. I hope more work on
clearing the simplify_subreg_operand code will be done for GCC-8 (at
least Matt Fortune expressed his willingness to do this).
Although it is better to avoid a wrong RTL code creation earlier, LRA
already can create a wrong code during its work for a long period of
time. It already happens for some cases.
So please commit your patch, Allan. But before doing it also please
check that the patch does not creates problems on x86-64 bootstrap and
GCC tests.
Thank you.
