[Bug rtl-optimization/17791] New: [4.0 Regression] doloop can produce wrong code causes Ada bootstrap failure

["pinskia at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

After fixing PR 17790, I noticed that Ada still does not bootstrap and looked into it and noticed that 
doloop is causing wrong code:
The RTL looks like:
(insn 334 333 429 27 /Volumes/UFS_Partition/pinskia/src/devel/new-fold/gcc/gcc/ada/csets.adb:
1151 (set (reg:SI 118 [ ivtmp.7 ])
        (const_int 255 [0xff])) 332 {*movsi_internal1} (nil)
    (nil))
...
(insn 359 358 360 28 /Volumes/UFS_Partition/pinskia/src/devel/new-fold/gcc/gcc/ada/csets.adb:
1151 (set (reg:SI 278)
        (plus:SI (reg:SI 118 [ ivtmp.7 ])
            (const_int -1 [0xffffffffffffffff]))) -1 (nil)
    (nil))

(insn 360 359 361 28 /Volumes/UFS_Partition/pinskia/src/devel/new-fold/gcc/gcc/ada/csets.adb:
1151 (set (reg:SI 118 [ ivtmp.7 ])
        (zero_extend:SI (subreg:QI (reg:SI 278) 3))) -1 (nil)
    (nil))

(note 361 360 362 28 ("/Volumes/UFS_Partition/pinskia/src/devel/new-fold/gcc/gcc/ada/
csets.adb") 1150)

(insn 362 361 363 28 /Volumes/UFS_Partition/pinskia/src/devel/new-fold/gcc/gcc/ada/csets.adb:
1150 (set (reg:CC 279)
        (compare:CC (reg:SI 118 [ ivtmp.7 ])
            (const_int 0 [0x0]))) -1 (nil)
    (nil))

-- 
           Summary: [4.0 Regression] doloop can produce wrong code causes
                    Ada bootstrap failure
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: wrong-code, build
          Severity: critical
          Priority: P2
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: powerpc-apple-darwin


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17791