This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug rtl-optimization/39077] [4.3/4.4/4.5 Regression] GCSE-optimization causes enormous binary size increase (~20 times !)
- From: "steven at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 12 Apr 2009 23:46:22 -0000
- Subject: [Bug rtl-optimization/39077] [4.3/4.4/4.5 Regression] GCSE-optimization causes enormous binary size increase (~20 times !)
- References: <bug-39077-17262@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #13 from steven at gcc dot gnu dot org 2009-04-12 23:46 -------
The real bug is that somehow MEM_ATTRS are not shared anymore. We have lots
and lots of exactly the same expression in the table, e.g.:
Index 3 (hash value 4232)
(mem/s/f/c:SI (plus:SI (reg/f:SI 20 frame)
(const_int -3828 [0xfffffffffffff10c])) [32 cpy.d+0 S4 A32])
Index 6 (hash value 4232)
(mem/s/f/c:SI (plus:SI (reg/f:SI 20 frame)
(const_int -3828 [0xfffffffffffff10c])) [32 cpy.d+0 S4 A32])
Index 10 (hash value 4232)
(mem/s/f/c:SI (plus:SI (reg/f:SI 20 frame)
(const_int -3828 [0xfffffffffffff10c])) [32 cpy.d+0 S4 A32])
but exp_equiv_p() thinks these are not equivalent, because the MEM_ATTRS
pointers are not the same. We should have MEM_ATTRS(x)==MEM_ATTRS(y) for two
MEMs with the same memory attributes, but here the pointers are not the same.
So we're allocating MEM_ATTRS somewhere without going via the table, or we're
adjusting MEM_ATTRS somewhere wvia an incorrect interface.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39077