------- Comment #2 from rearnsha at gcc dot gnu dot org 2008-12-16 17:12
-------
Confirmed. This appears to be a bug in the register-renaming pass, where the
insn
(insn:HI 84 79 82 8 proc/sysinfo.c:890 (parallel [
(set (reg:CC_NOOV 24 cc)
(compare:CC_NOOV (minus:SI (ashiftrt:SI (reg:SI 2 r2 [170])
(const_int 2 [0x2]))
(reg:SI 3 r3 [173]))
(const_int 0 [0x0])))
(set (reg/v:SI 0 r0 [orig:133 rc.187 ] [133])
(minus:SI (ashiftrt:SI (reg:SI 2 r2 [170])
(const_int 2 [0x2]))
(reg:SI 3 r3 [173])))
]) 265 {*arith_shiftsi_compare0} (nil))
is transformed to
(insn:HI 84 79 82 8 proc/sysinfo.c:890 (parallel [
(set (reg:CC_NOOV 24 cc)
(compare:CC_NOOV (minus:SI (ashiftrt:SI (reg:SI 2 r2 [170])
(const_int 2 [0x2]))
(reg:SI 14 lr [173]))
(const_int 0 [0x0])))
(set (reg/v:SI 0 r0 [orig:133 rc.187 ] [133])
(minus:SI (cc0)
(cc0)))
]) 265 {*arith_shiftsi_compare0} (expr_list:REG_DEAD (reg:SI 3 r3
[173])
(expr_list:REG_DEAD (reg:SI 2 r2 [170])
(nil))))
The use of cc0 in the second version indicates a failure to correctly transform
the insn.
The bug goes away if -frename-registers is removed from the command line.
--
rearnsha at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rearnsha at gcc dot gnu dot
| |org
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Known to fail| |4.3.3
Known to work| |4.4.0
Last reconfirmed|0000-00-00 00:00:00 |2008-12-16 17:12:19
date| |
Target Milestone|--- |4.3.4
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36209
