[PATCH] Avoid UBSAN -fsanitize=enum errors on GCC memmodel enum (PR rtl-optimization/84643)

[Richard Biener]

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