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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/50460] [4.7 Regression] __builtin___strcpy_chk/__builtin_object_size don't work Date: Wed, 28 Sep 2011 12:29:00 -0000 [thread overview] Message-ID: <bug-50460-4-HfONlI1Y36@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-50460-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50460 Richard Guenther <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |diagnostic --- Comment #7 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-09-28 12:23:15 UTC --- Btw, this is equivalent to a missing diagnostic, it's correctly not trapping similar as to if it didn't know anything about the object that is refered to. Indeed when I disable the folding during gimplification CCP comes along and does <bb 2>: str1.0_1 = str1; D.2732_2 = str1.0_1 + 5; - D.2733_3 = &a.buf1 + 4; - __dest_7 = (char * restrict) D.2733_3; __src_8 = (const char * restrict) D.2732_2; - D.2747_9 = __builtin_object_size (__dest_7, 1); - D.2746_10 = __builtin___strcpy_chk (__dest_7, __src_8, D.2747_9); - D.2746_12 = D.2746_10; - D.2734_4 = 0; - return D.2734_4; + D.2746_10 = __builtin___strcpy_chk (&MEM[(void *)&a + 4B], __src_8, 6); + return 0; which is good, as the address is invariant. So, short of moving the objsize pass way earlier (which I'm sure we don't want to do), I don't see a good way to recover this diagnostic. One possibility is to make sure try_move_mult_to_index handles the case of &a.buf1 + 4, instead of just &a.buf1[0] + 4. I have a patch for that.
next prev parent reply other threads:[~2011-09-28 12:27 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-09-20 8:16 [Bug middle-end/50460] New: " hjl.tools at gmail dot com 2011-09-20 10:49 ` [Bug middle-end/50460] " jakub at gcc dot gnu.org 2011-09-20 13:47 ` hjl.tools at gmail dot com 2011-09-22 22:06 ` rguenth at gcc dot gnu.org 2011-09-23 8:34 ` jakub at gcc dot gnu.org 2011-09-25 11:24 ` rguenth at gcc dot gnu.org 2011-09-26 9:14 ` jakub at gcc dot gnu.org 2011-09-28 12:29 ` rguenth at gcc dot gnu.org [this message] 2011-09-28 13:52 ` rguenth at gcc dot gnu.org 2011-09-28 14:01 ` rguenth at gcc dot gnu.org
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