Re: [PR65768] Check rtx_cost when propagating constant

[Jeff Law]

On 05/13/2015 11:46 PM, Kugan wrote:

ping?

Thanks,
Kugan

On 15/04/15 17:53, Kugan wrote:

As mentioned in PR65768, ARM gcc generates suboptimal code for constant
Uses in loop. Part of the reason is cprop is undoing what loop invariant
code motion did.

Zhenqiang posted a patch at to fix this based on rtx costs:
https://gcc.gnu.org/ml/gcc-patches/2014-06/msg01321.html

I cleaned it up and bootstrapped, regression tested on x86_64-linux-gnu;
no new regressions. Is this OK for trunk?

Thanks,
Kugan

gcc/ChangeLog:

2015-04-15  Kugan Vivekanandarajah  <kug...@linaro.org>
            Zhenqiang Chen  <zhenqiang.c...@linaro.org>

        PR target/65768
        * cprop.c (try_replace_reg): Check cost of constants before propagating.

I should have also noted, fresh bootstrap & regression test is needed too.

jeff