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Re: [PATCH] Fix RTL DCE with separate shrink wrapped epilogues (PR rtl-optimization/83985)
- From: Segher Boessenkool <segher at kernel dot crashing dot org>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: Richard Biener <rguenther at suse dot de>, Jeff Law <law at redhat dot com>, Eric Botcazou <ebotcazou at adacore dot com>, gcc-patches at gcc dot gnu dot org
- Date: Thu, 25 Jan 2018 17:48:52 -0600
- Subject: Re: [PATCH] Fix RTL DCE with separate shrink wrapped epilogues (PR rtl-optimization/83985)
- Authentication-results: sourceware.org; auth=none
- References: <20180125222033.GT2063@tucnak>
On Thu, Jan 25, 2018 at 11:20:33PM +0100, Jakub Jelinek wrote:
> Hi!
>
> The r241060 change added the second hunk in this patch which the patch is
> reverting. The problem is that not deleting some unmarked insns in
> delete_unmarked_insns is done in a wrong place, it causes indeed not to
> delete the instruction we don't want to DCE, but the instructions that
> are needed by the instructions (in this case a memory load whose result
> the REG_CFA_RESTORE instruction uses) are not marked either and those are
> deleted.
>
> The following patch fixes it by making such instructions non-deletable,
> which means they are marked and the DCE algorithm then marks the
> instructions they need too.
Looks good to me! Thanks. And sorry for causing the bug in the first
place :-/
Segher