[Bug rtl-optimization/25130] [4.1/4.2 Regression] miscompilation in GCSE

steven at gcc dot gnu dot org gcc-bugzilla@gcc.gnu.org
Sun Dec 18 00:49:00 GMT 2005



------- Comment #10 from steven at gcc dot gnu dot org  2005-12-18 00:49 -------
At -O1 (i.e. for my test case) CSE1 turns this...

(insn 24 22 25 0 (parallel [
            (set (reg/f:SI 67)
                (plus:SI (reg/f:SI 20 frame)
                    (const_int -16 [0xfffffff0])))
            (clobber (reg:CC 17 flags))
        ]) 148 {*addsi_1} (nil)
    (nil))

(insn 25 24 27 0 (parallel [
            (set (reg/f:SI 61 [ this.1 ])
                (plus:SI (reg/f:SI 67)
                    (const_int 4 [0x4])))
            (clobber (reg:CC 17 flags))
        ]) 148 {*addsi_1} (nil)
    (nil))

(insn 27 25 28 0 (set (reg:SI 68 [ <variable>._M_impl._M_start_node ])
        (mem/s/j:SI (plus:SI (reg/f:SI 61 [ this.1 ])
                (const_int 4 [0x4])) [0 <variable>._M_impl._M_start_node+0 S4
A32])) 34 {*movsi_1} (nil)
    (nil))


...into this...

(insn 27 22 28 0 (set (reg:SI 68 [ <variable>._M_impl._M_start_node ])
        (mem/s/j:SI (plus:SI (reg/f:SI 20 frame)
                (const_int -8 [0xfffffff8])) [0
<variable>._M_impl._M_start_node+0 S4 A32])) 34 {*movsi_1} (nil)
    (nil))


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25130



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