[dataflow] [RFC] Remove many almost useless DCE passes

[Vladimir Makarov]

Steven Bosscher wrote:

> On 2/27/07, Vladimir Makarov <vmakarov@redhat.com> wrote:
>
>> Good because SPECFP2000 for ppc64 is 0.5% better (SPECInt2000 is the
>> same) on the branch than on the mainline at the last merge point.  And
>> this patch could remove this achievement.
>
>
> Or it might not make a difference at all.
>
> Which is actually more likely IMHO, but I'll let the numbers speak for
> me, instead of doing some hand waiving and speculating.
>
You was right.  The patch make the compiler a bit faster and a bit 
better with the point of performance at least for ppc64.  May it will be 
interesting for you.  Here is the data for ppc64 (2.5 Ghz PPC970FX).

Base: before the patch (-O2)
Peak: after the patch (-O2)

========================================================================
164.gzip          1400   190       739    *     1400   189       740    *
175.vpr           1400   308       454    *     1400   309       454    *
176.gcc                                   X                             X
181.mcf           1800   535       337    *     1800   537       335    *
186.crafty        1000    86.6    1155    *     1000    87.2    1147    *
197.parser        1800   343       525    *     1800   342       527    *
252.eon           1300   113      1154    *     1300   115      1132    *
253.perlbmk       1800   243       739    *     1800   245       736    *
254.gap           1100   152       722    *     1100   152       723    *
255.vortex        1900   235       807    *     1900   221       858    *
256.bzip2         1500   253       593    *     1500   253       592    *
300.twolf                                 X                             X
Est. SPECint_base2000              677    
Est. SPECint2000                                                 679    

========================================================================
168.wupwise       1600       155      1032*     1600       157      1018*
171.swim          3100      1159       267*     3100      1159       267*
172.mgrid         1800       285       632*     1800       285       632*
173.applu         2100       299       703*     2100       296       711*
177.mesa          1400       142       989*     1400       141       996*
178.galgel        2900       690       421*     2900       689       421*
179.art           2600       396       657*     2600       397       655*
183.equake        1300       136       959*     1300       135       960*
187.facerec       1900       213       892*     1900       203       936*
188.ammp          2200       564       390*     2200       564       390*
189.lucas         2000       221       906*     2000       221       907*
191.fma3d         2100       231       909*     2100       232       904*
200.sixtrack      1100       363       303*     1100       358       307*
301.apsi          2600       448       581*     2600       446       583*
Est. SPECfp_base2000                   632
Est. SPECfp2000                                                      635

Compilation time

INT without twolf:
Base:
real	7m32.027s
user	6m40.094s
sys	0m29.926s

peak:
real	7m39.357s
user	6m39.559s
sys	0m29.911s

FP:
base:
real	6m52.848s
user	6m3.951s
sys	0m25.355s

peak:
real	6m44.545s
user	6m3.576s
sys	0m25.095s

Code size change/base/peak (text segment)

----------------CINT2000-----------------
 0.000%          46542          46542 164.gzip
-0.049%         163913         163833 175.vpr
-0.007%        1504222        1504110 176.gcc
 0.114%          14064          14080 181.mcf
 0.016%         195381         195413 186.crafty
-0.063%         126698         126618 197.parser
 0.002%         421115         421123 252.eon
 0.003%         629279         629295 253.perlbmk
 0.000%         579926         579926 254.gap
-0.027%         653406         653230 255.vortex
=0.000%          39422          39422 256.bzip2
Average = -0.000782929%

----------------CFP2000-----------------
 0.111%          28723          28755 168.wupwise
 0.150%          10678          10694 171.swim
=0.000%          16887          16887 172.mgrid
 0.033%          49094          49110 173.applu
 0.000%         579469         579469 177.mesa
 0.028%         226460         226524 178.galgel
=0.000%          18296          18296 179.art
 0.234%          20506          20554 183.equake
-0.024%          66766          66750 187.facerec
 0.000%         132960         132960 188.ammp
 0.000%          44718          44718 189.lucas
 0.072%         996921         997641 191.fma3d
-0.320%         859844         857092 200.sixtrack
-0.023%         137088         137056 301.apsi
Average = 0.0153551%