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From: "glisse at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/60770] disappearing clobbers
Date: Sun, 22 Jun 2014 21:07:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60770

--- Comment #5 from Marc Glisse <glisse at gcc dot gnu.org> ---
Looking at comment #1 more closely, the problem is not with CCP, which
produces:

q = n_2(D);
q ={v} {CLOBBER};
_6 = q;
return _6;

The problem is during the TODO, in execute_update_addresses_taken, which finds
out that q does not need its address taken anymore, and

                /* For var ={v} {CLOBBER}; where var lost
                   TREE_ADDRESSABLE just remove the stmt.  */

Maybe it could instead create an uninitialized ssa_name for var.