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Re: [patch,opencc] Don't mark OpenACC auto loops as independent inside acc parallel regions
- From: Julian Brown <julian at codesourcery dot com>
- To: Cesar Philippidis <cesar at codesourcery dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, "Schwinge, Thomas" <Thomas_Schwinge at mentor dot com>
- Date: Tue, 4 Dec 2018 00:07:41 +0000
- Subject: Re: [patch,opencc] Don't mark OpenACC auto loops as independent inside acc parallel regions
- References: <email@example.com>
On Thu, 20 Sep 2018 09:49:43 -0700
Cesar Philippidis <firstname.lastname@example.org> wrote:
> OpenACC as a concept of loop independence, in which independent loops
> may be executed in parallel across gangs, workers and vectors. Inside
> acc parallel regions, if a loop isn't explicitly marked seq or auto,
> it is predetermined to be independent.
> This patch corrects a bug where acc loops marked as auto were being
> mistakenly promoted to independent. That's bad because it can generate
> bogus results if a dependency exist.
> Note that this patch depends on the following patches for
> -fnote-info-omp-optimized which is used in a test case.
> * Add user-friendly OpenACC diagnostics regarding detected
> * Correct the reported line number in fortran combined OpenACC
> * Correct the reported line number in c++ combined OpenACC
> directives https://gcc.gnu.org/ml/gcc-patches/2018-07/msg01552.html
> Is this OK for trunk? I bootstrapped and regtested on x86_64 Linux
> with nvptx offloading.