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[Bug tree-optimization/33302] dead-store not eliminated
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 6 Sep 2007 12:13:43 -0000
- Subject: [Bug tree-optimization/33302] dead-store not eliminated
- References: <bug-33302-8535@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #11 from rguenth at gcc dot gnu dot org 2007-09-06 12:13 -------
The extra store you still see is caused by -ftracer duplicating it.
Optimizations
after that don't catch that (because of the intervening possibly aliasing loads
I guess):
(insn 25 24 27 4 t.ii:3 (set (mem/s:SI (reg/f:DI 102) [4 <variable>.D.2014.a+0
S4 A64])
(reg:SI 75)) 47 {*movsi_1} (expr_list:REG_DEAD (reg:SI 75)
(expr_list:REG_EQUAL (plus:SI (mem/s:SI (reg/f:DI 102) [4
<variable>.D.2014.a+0 S4 A64])
(const_int 4 [0x4]))
(nil))))
(insn 27 25 28 4 t.ii:18 (set (reg:DI 78 [ <variable>.addr ])
(zero_extend:DI (mem/s:SI (reg/f:DI 101) [4 <variable>.addr+0 S4
A64]))) 120 {zero_extendsidi2_rex64} (nil))
...
(insn 96 95 97 4 t.ii:3 (parallel [
(set (reg:SI 83)
(plus:SI (reg:SI 76 [ <variable>.D.2014.a ])
(const_int 6 [0x6])))
(clobber (reg:CC 17 flags))
]) 235 {*addsi_1} (expr_list:REG_UNUSED (reg:CC 17 flags)
(expr_list:REG_DEAD (reg:SI 84 [ <variable>.D.2014.a ])
(nil))))
(insn 97 96 98 4 t.ii:3 (set (mem/s:SI (reg/f:DI 102) [4 <variable>.D.2014.a+0
S4 A64])
(reg:SI 83)) 47 {*movsi_1} (expr_list:REG_EQUAL (plus:SI (mem/s:SI
(reg/f:DI 102) [4 <variable>.D.2014.a+0 S4 A64])
(const_int 2 [0x2]))
(expr_list:REG_DEAD (reg:SI 83)
(nil))))
If you build without -ftracer or without -fforce-addr it works (but won't
combine the add on one path). But.. -ftracer was supposed to be moved
to the tree level...
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33302