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From: "vries at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/67955] tree-dse does not use pointer info Date: Tue, 13 Oct 2015 15:34:00 -0000 [thread overview] Message-ID: <bug-67955-4-q3qgihV8PU@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-67955-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67955 --- Comment #2 from vries at gcc dot gnu.org --- (In reply to Richard Biener from comment #1) > The same points-to set results from > > int *p = (int *)((char *)&a + 2); > > or even > > int *p = &a + 1; > I see, I didn't realize that. But AFAICT, in both these cases, storing to *p is illegal (if 'a' is a scalar int). > so you can't use points-to info that way (to derive a must-alias). I see your point related to an array object, there pointers to different array elements would have identical points-to sets. I wonder though: if we have a store '*p = 0', and the size of the store is the same as the size of the pointed-to object of pointer p, can't we conclude that pointer p points to the start of the object?
next prev parent reply other threads:[~2015-10-13 15:34 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-10-13 13:57 [Bug tree-optimization/67955] New: " vries at gcc dot gnu.org 2015-10-13 14:25 ` [Bug tree-optimization/67955] " rguenth at gcc dot gnu.org 2015-10-13 15:34 ` vries at gcc dot gnu.org [this message] 2015-10-14 7:28 ` rguenth at gcc dot gnu.org 2015-10-14 11:06 ` vries at gcc dot gnu.org 2015-10-14 12:18 ` vries at gcc dot gnu.org 2015-10-14 14:56 ` vries at gcc dot gnu.org 2015-10-15 6:32 ` vries at gcc dot gnu.org 2015-10-15 6:32 ` vries at gcc dot gnu.org
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