> On May 11, 2023, at 11:05 AM, Hans-Peter Nilsson via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
>
> ...
> Yes, very interesting. Thank you for sharing this. I've
> seen regressions with LRA for CRIS too, for
> "double-register-sized" types, which for CRIS, a 32-bit
> target, translates to 64-bit types (DFmode and DImode), and
> where LRA does a much worse job than reload; spills a lot
> more often to stack, even after trying every
> register-allocation-related hook I found (and also an LRA
> patch which helped only by a fraction, but regressed results
> on x86_64-linux, so let's quickly forget it again).
That observation makes me a bit worried. While CRIS may not be a priority
platform, that description makes it sound like a case that would be significant
in any 32 bit platform, which would include priority ones like i386 and ARM.
If that's true, I wonder about dropping Reload. While I understand it's been
years since LRA was first introduced, wouldn't we even so want to go by the
rule that a newer replacement mechanism doesn't replace an older one until the
replacement demonstrates comparable or better output compared with the older
one?
paul
