[Bug tree-optimization/32921] [4.3 Regression] Revision 126326 causes 12% slowdown

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

------- Comment #12 from pthaugen at gcc dot gnu dot org  2007-10-17 16:18 -------
And now some comments to go with the prior attatchment...

This checkin is causing a 75% degradation on leslie3d for PowerPC. As HJ
observed earlier, it depends on a second function accessing some of the global
data.

Generated code for simple copy loop in EXTRAPI(), compiled with -O2.

revision 126325:

        .p2align 4,,15
.L3:
        lfd 0,0(11)      #* ivtmp.71, tmp198
        add 11,11,6      # ivtmp.71, ivtmp.71, ivtmp.77
        stfd 0,0(9)      #* ivtmp.76, tmp198
        add 9,9,5        # ivtmp.76, ivtmp.76, ivtmp.73
        bdnz .L3         #


revision 126326:

        .p2align 4,,15
.L6:
        lwz 10,12(27)    # <variable>.stride, prephitmp.66
        lwz 3,12(28)     # <variable>.stride, prephitmp.56
.L3:
        mullw 10,10,12   # tmp141, prephitmp.66, i
        lwz 9,36(30)     # <variable>.stride, <variable>.stride
        lwz 0,36(31)     # <variable>.stride, <variable>.stride
        lwz 8,4(30)      # uav.offset, uav.offset
        lwz 11,4(31)     # qav.offset, qav.offset
        lwz 6,24(30)     # <variable>.stride, <variable>.stride
        lwz 7,24(31)     # <variable>.stride, <variable>.stride
        lwz 4,0(30)      # uav.data, uav.data
        lwz 5,0(31)      # qav.data, qav.data
        mullw 3,3,12     # tmp160, prephitmp.56, i
        slwi 9,9,1       # tmp142, <variable>.stride,
        slwi 0,0,1       # tmp161, <variable>.stride,
        add 9,9,8        # tmp143, tmp142, uav.offset
        add 0,0,11       # tmp162, tmp161, qav.offset
        add 9,9,6        # tmp145, tmp143, <variable>.stride
        add 0,0,7        # tmp164, tmp162, <variable>.stride
        add 9,9,10       # tmp147, tmp145, tmp141
        add 0,0,3        # tmp166, tmp164, tmp160
        slwi 9,9,3       # tmp148, tmp147,
        slwi 0,0,3       # tmp167, tmp166,
        addi 12,12,1     # i, i,
        lfdx 0,5,0       #* qav.data, tmp169
        cmpw 7,12,29     # imax.3, tmp170, i
        stfdx 0,9,4      #* uav.data, tmp169
        bne 7,.L6        #


-- 

pthaugen at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pthaugen at gcc dot gnu dot
                   |                            |org, bergner at gcc dot gnu
                   |                            |dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32921