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Re: [PATCH] Avoid UBSAN -fsanitize=enum errors on GCC memmodel enum (PR rtl-optimization/84643)
- From: Richard Biener <rguenther at suse dot de>
- To: Jakub Jelinek <jakub at redhat dot com>,Jeff Law <law at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Mon, 19 Mar 2018 21:35:57 +0100
- Subject: Re: [PATCH] Avoid UBSAN -fsanitize=enum errors on GCC memmodel enum (PR rtl-optimization/84643)
- References: <20180319193920.GP8577@tucnak>
On March 19, 2018 8:39:20 PM GMT+01:00, Jakub Jelinek <jakub@redhat.com> wrote:
>Hi!
>
>The enum memmodel doesn't declare the target specific enumerators,
>which are just defines in i386.h, but as those are above any
>enumerators in the generic enum, it is strictly speaking UB when
>values with that enum memmodel type have the higher target dependent
>bits
>set. This patch just makes sure that the enumerator is full signed
>32-bit.
>
>Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
Richard.
>2018-03-19 Jakub Jelinek <jakub@redhat.com>
>
> PR rtl-optimization/84643
> * memmodel.h (enum memmodel): Add MEMMODEL_MAX enumerator.
>
>--- gcc/memmodel.h.jj 2018-01-03 10:19:55.495534012 +0100
>+++ gcc/memmodel.h 2018-03-19 10:31:42.980812157 +0100
>@@ -45,7 +45,9 @@ enum memmodel
> MEMMODEL_LAST = 6,
> MEMMODEL_SYNC_ACQUIRE = MEMMODEL_ACQUIRE | MEMMODEL_SYNC,
> MEMMODEL_SYNC_RELEASE = MEMMODEL_RELEASE | MEMMODEL_SYNC,
>- MEMMODEL_SYNC_SEQ_CST = MEMMODEL_SEQ_CST | MEMMODEL_SYNC
>+ MEMMODEL_SYNC_SEQ_CST = MEMMODEL_SEQ_CST | MEMMODEL_SYNC,
>+ /* Say that all the higher bits are valid target extensions. */
>+ MEMMODEL_MAX = INTTYPE_MAXIMUM (int)
> };
>
> /* Return the memory model from a host integer. */
>
> Jakub