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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug jit/66812] jit code-generation example that unexpectedly required -fno-strict-aliasing to work Date: Thu, 09 Jul 2015 20:43:00 -0000 [thread overview] Message-ID: <bug-66812-4-7vPQuvMWqn@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-66812-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66812 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |alias, wrong-code --- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> --- This sounds like there is an aliasing set problem. In the C front-end we have: 5174 /* Permit type-punning when accessing a union, provided the access 5175 is directly through the union. For example, this code does not 5176 permit taking the address of a union member and then storing 5177 through it. Even the type-punning allowed here is a GCC 5178 extension, albeit a common and useful one; the C standard says 5179 that such accesses have implementation-defined behavior. */ 5180 for (u = t; 5181 TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF; 5182 u = TREE_OPERAND (u, 0)) 5183 if (TREE_CODE (u) == COMPONENT_REF 5184 && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE) 5185 return 0; 5186 In c_common_get_alias_set . Maybe that is missing on the libjit side.
next prev parent reply other threads:[~2015-07-09 20:43 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-07-08 14:27 [Bug jit/66812] New: jit code-generation example that " dmalcolm at gcc dot gnu.org 2015-07-09 19:09 ` [Bug jit/66812] jit code-generation example that unexpectedly " dmalcolm at gcc dot gnu.org 2015-07-09 19:11 ` dmalcolm at gcc dot gnu.org 2015-07-09 19:13 ` dmalcolm at gcc dot gnu.org 2015-07-09 19:16 ` dmalcolm at gcc dot gnu.org 2015-07-09 19:19 ` dmalcolm at gcc dot gnu.org 2015-07-09 20:43 ` pinskia at gcc dot gnu.org [this message] 2015-07-09 21:02 ` dmalcolm at gcc dot gnu.org 2015-07-09 21:03 ` dmalcolm at gcc dot gnu.org 2015-07-09 21:04 ` dmalcolm at gcc dot gnu.org 2015-07-09 21:35 ` dmalcolm at gcc dot gnu.org
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