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From: "hjl dot tools at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/44542] expand_one_stack_var_at may set DECL_ALIGN to a too high value Date: Wed, 16 Jun 2010 14:36:00 -0000 [thread overview] Message-ID: <20100616143630.19398.qmail@sourceware.org> (raw) In-Reply-To: <bug-44542-87@http.gcc.gnu.org/bugzilla/> ------- Comment #14 from hjl dot tools at gmail dot com 2010-06-16 14:36 ------- The code in question is offset -= frame_phase; align = offset & -offset; align *= BITS_PER_UNIT; if (align == 0) align = STACK_BOUNDARY; else if (align > MAX_SUPPORTED_STACK_ALIGNMENT) align = MAX_SUPPORTED_STACK_ALIGNMENT; offset is computed from align = get_decl_align_unit (SSAVAR (var)); offset = alloc_stack_frame_space (size, align); If you compute alignment from offset again, you will get a number >= requested alignment. That is when we allocate 8byte aligned at 8byte from stack, we may get offset 8, 16, 24, 32, 40, 48, 56, 64, ... depending on how much we have allocated on stack. As for MAX_SUPPORTED_STACK_ALIGNMENT, I doubt we will hit it since it is a huge number. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44542
next prev parent reply other threads:[~2010-06-16 14:36 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-06-15 10:51 [Bug target/44542] New: " jakub at gcc dot gnu dot org 2010-06-15 11:19 ` [Bug target/44542] " matz at gcc dot gnu dot org 2010-06-15 11:37 ` jakub at gcc dot gnu dot org 2010-06-15 12:53 ` jakub at gcc dot gnu dot org 2010-06-15 13:41 ` matz at gcc dot gnu dot org 2010-06-15 13:51 ` matz at gcc dot gnu dot org 2010-06-15 14:47 ` hjl dot tools at gmail dot com 2010-06-15 14:56 ` matz at gcc dot gnu dot org 2010-06-15 15:39 ` hjl dot tools at gmail dot com 2010-06-15 16:46 ` jakub at gcc dot gnu dot org 2010-06-15 17:13 ` hjl dot tools at gmail dot com 2010-06-15 17:20 ` hjl dot tools at gmail dot com 2010-06-15 17:25 ` hjl dot tools at gmail dot com 2010-06-16 6:56 ` jakub at gcc dot gnu dot org 2010-06-16 14:36 ` hjl dot tools at gmail dot com [this message] 2010-06-16 14:58 ` jakub at gcc dot gnu dot org 2010-06-16 15:38 ` hjl dot tools at gmail dot com 2010-07-27 17:55 ` jakub at gcc dot gnu dot org 2010-07-27 18:00 ` jakub at gcc dot gnu dot org 2010-09-17 20:25 ` hjl dot tools at gmail dot com
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