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Re: [RFC] Unconditionally clean up CFG before emitting prologue
- From: Richard Guenther <richard dot guenther at gmail dot com>
- To: Eric Botcazou <ebotcazou at adacore dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Mon, 9 Apr 2012 13:07:41 +0200
- Subject: Re: [RFC] Unconditionally clean up CFG before emitting prologue
- References: <201204091155.26101.ebotcazou@adacore.com>
On Mon, Apr 9, 2012 at 11:55 AM, Eric Botcazou <ebotcazou@adacore.com> wrote:
> Hi,
>
> with the numerous checks generated in Ada, the gimplification process can
> generated dead branches that aren't easily eliminated at -O0 and can impair
> the debugging experience. ?We have found that unconditionally cleaning up the
> CFG before emitting the prologue/epilogue can help in some cases. ?This is the
> same idiom already used in rest_of_handle_jump2 for example.
>
> Tested on x86_64-suse-linux. ?Comments?
Isn't the gimple cfg-cleanup we run post optimization (right before expansion)
not enough? Or the cfg-cleanup we perform right after expansion now?
At least if the branches are really caused by the gimplification process I would
expect things to be cleaned up at this point, no?
Richard.
>
>
> 2012-04-09 ?Eric Botcazou ?<ebotcazou@adacore.com>
>
> ? ? ? ?* function.c (rest_of_handle_thread_prologue_and_epilogue): Clean up
> ? ? ? ?the CFG before generating prologue/epilogue even when not optimizing.
>
>
> --
> Eric Botcazou