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Re: [PATCH] Fix PR71815 (SLSR misses PHI opportunities)
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Bill Schmidt <wschmidt at linux dot vnet dot ibm dot com>
- Cc: Richard Biener <richard dot guenther at gmail dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 26 Jun 2017 12:22:40 -0700
- Subject: Re: [PATCH] Fix PR71815 (SLSR misses PHI opportunities)
- Authentication-results: sourceware.org; auth=none
- References: <f30ac263-bc14-e3af-d178-69777bedcd2c@linux.vnet.ibm.com> <CAFiYyc3HQTTzRZ7Qf3iVEq6YgxE1hoar-vHs8W-Wt_zmNCi=Jg@mail.gmail.com> <7cb51e30-ad7d-d3a4-c04b-22fb2a0c2f13@linux.vnet.ibm.com>
On Fri, Jun 23, 2017 at 9:06 AM, Bill Schmidt
<wschmidt@linux.vnet.ibm.com> wrote:
> Hi,
>
> Here's version 2 of the patch to fix the missed SLSR PHI opportunities,
> addressing Richard's comments. I've repeated regstrap and SPEC testing
> on powerpc64le-unknown-linux-gnu, again showing the patch as neutral
> with respect to performance. Is this ok for trunk?
>
> Thanks for the review!
>
> Bill
>
>
> [gcc]
>
> 2016-06-23 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
>
> * gimple-ssa-strength-reduction.c (uses_consumed_by_stmt): New
> function.
> (find_basis_for_candidate): Call uses_consumed_by_stmt rather than
> has_single_use.
> (slsr_process_phi): Likewise.
> (replace_uncond_cands_and_profitable_phis): Don't replace a
> multiply candidate with a stride of 1 (copy or cast).
> (phi_incr_cost): Call uses_consumed_by_stmt rather than
> has_single_use.
> (lowest_cost_path): Likewise.
> (total_savings): Likewise.
>
This may have caused:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81216
--
H.J.