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Re: FRE - SCCVN problem with initialized global variables

From: Andreas Krebbel <Andreas dot Krebbel at de dot ibm dot com>
To: Daniel Berlin <dberlin at dberlin dot org>
Cc: gcc at gcc dot gnu dot org
Date: Mon, 23 Jul 2007 17:57:42 +0200
Subject: Re: FRE - SCCVN problem with initialized global variables
References: <20070718165356.GA9333@blc4eb430604175.ibm.com> <4aca3dc20707181206i19b8971et761b3f85a51fdf29@mail.gmail.com>

> We explicitly pull out initializers from variables that are:
>  /* Pull out any truly constant values.  */
>          if (TREE_READONLY (rhs)
>              && TREE_STATIC (rhs)
>              && DECL_INITIAL (rhs)
>              && valid_gimple_expression_p (DECL_INITIAL (rhs)))
>            return DECL_INITIAL (rhs);

It turned out that this check was miscompiled by ifcombine when
merging the TREE_READONLY and the TREE_STATIC bit checks:

http://gcc.gnu.org/ml/gcc-patches/2007-07/msg01668.html

Thanks for the pointer.

Bye,

-Andreas-

References:
- FRE - SCCVN problem with initialized global variables
  - From: Andreas Krebbel
- Re: FRE - SCCVN problem with initialized global variables
  - From: Daniel Berlin

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