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[Bug rtl-optimization/50063] [4.6/4.7 Regression] DSE: wrong code for gcc.dg/torture/pta-ptrarith-3.c
- From: "jakub at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 19 Dec 2011 19:12:56 +0000
- Subject: [Bug rtl-optimization/50063] [4.6/4.7 Regression] DSE: wrong code for gcc.dg/torture/pta-ptrarith-3.c
- Auto-submitted: auto-generated
- References: <bug-50063-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50063
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P2 |P4
--- Comment #14 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-12-19 19:12:56 UTC ---
Well, it is certainly desirable not to process the prologue insns during
init_alias_analysis. The fact that stack pointer has the same value as frame
pointer after the prologue is not usual and something the generic code isn't
prepared for (usually either frame pointer is eliminated (of course then the
register can be used for something else) or frame pointer is initialized from
stack pointer and then decremented (or incremented) still inside of the
prologue).
So you need to tell the alias analysis about that, as the prologue isn't
scanned, it is the backend responsibility to tell that.