Documentation: Additional optimization levels for ARM/Linux (#6548)
Documentation: Additional optimization levels for ARM/Linux (#6548)

This instruction is to enable -Ofast or -Oz optimization level of clang on ARM/Linux.
Below is file-size comparison result of major components among -O3, -Ofast,
and -Oz on ARM/Linux-based Raspberry Pi2 board (Ubuntu/ARM 14.04 32bit).

* Linux/ARM: Release Build + O3(default): stripped , commit: 561b64d2c210b4d999de7f1ac55756704eaba784 (Jul-26-2016)
------------------------------------------------------------------------------------------------------------------
-rwxr-xr-x 1 leemgs leemgs     18,472 Jul 27 16:14 corerun
-rwxr-xr-x 1 leemgs leemgs  1,512,828 Jul 27 18:33 libclrjit.so
-rwxr-xr-x 1 leemgs leemgs  4,525,328 Jul 27 18:33 libcoreclr.so
-rwxr--r-- 1 leemgs leemgs     29,696 Jul 27 00:55 ./mscorlib.dll
-rwxr--r-- 1 leemgs leemgs  2,211,840 Jul 27 00:54 ./System.Private.CoreLib.dll
Total:   8,298,164 bytes

* Linux/ARM: Release Build + Ofast: stripped , commit: 561b64d2c210b4d999de7f1ac55756704eaba784 (Jul-26-2016)
-------------------------------------------------------------------------------------------------------------
-rwxr-xr-x 1 leemgs leemgs    18,496 Jul 26 05:00 ./corerun
-rwxr-xr-x 1 leemgs leemgs 1,512,844 Jul 26 04:59 ./libclrjit.so
-rwxr-xr-x 1 leemgs leemgs 4,525,360 Jul 26 04:59 ./libcoreclr.so
-rwxr--r-- 1 leemgs leemgs    29,696 Jul 26 00:49 ./mscorlib.dll
-rwxr--r-- 1 leemgs leemgs 2,211,840 Jul 26 00:48 ./System.Private.CoreLib.dll
Total:   8,298,236 bytes

* Linux/ARM: Release Build + Oz: stripped , commit: 561b64d2c210b4d999de7f1ac55756704eaba784 (Jul-26-2016)
---------------------------------------------------------------------------------------------------------
-rwxr-xr-x 1 leemgs leemgs    14,400 Jul 29 05:02 ./corerun
-rwxr-xr-x 1 leemgs leemgs 1,181,160 Jul 29 04:40 ./libclrjit.so
-rwxr-xr-x 1 leemgs leemgs 3,407,200 Jul 29 04:40 ./libcoreclr.so
-rwxr--r-- 1 leemgs leemgs    29,696 Jul 29 00:49 ./mscorlib.dll
-rwxr--r-- 1 leemgs leemgs 2,211,840 Jul 29 00:48 ./System.Private.CoreLib.dll
Total:  6,844,296 bytes

Signed-off-by: Geunsik Lim <acd8f4539166019ed6425de5f67e6d834f46e5a4@samsung.com>
James-Ko/coreclr,krk/coreclr,AlexGhiondea/coreclr,YongseopKim/coreclr,ruben-ayrapetyan/coreclr,parjong/coreclr,kyulee1/coreclr,tijoytom/coreclr,dpodder/coreclr,naamunds/coreclr,hseok-oh/coreclr,ramarag/coreclr,krk/coreclr,mskvortsov/coreclr,neurospeech/coreclr,AlexGhiondea/coreclr,krk/coreclr,JosephTremoulet/coreclr,cmckinsey/coreclr,mmitche/coreclr,poizan42/coreclr,cshung/coreclr,poizan42/coreclr,Dmitry-Me/coreclr,krytarowski/coreclr,cydhaselton/coreclr,wateret/coreclr,cmckinsey/coreclr,cmckinsey/coreclr,Dmitry-Me/coreclr,JosephTremoulet/coreclr,krytarowski/coreclr,russellhadley/coreclr,tijoytom/coreclr,cydhaselton/coreclr,cydhaselton/coreclr,wateret/coreclr,rartemev/coreclr,jamesqo/coreclr,JonHanna/coreclr,naamunds/coreclr,cshung/coreclr,alexperovich/coreclr,James-Ko/coreclr,jhendrixMSFT/coreclr,JosephTremoulet/coreclr,qiudesong/coreclr,jhendrixMSFT/coreclr,bartdesmet/coreclr,naamunds/coreclr,JosephTremoulet/coreclr,neurospeech/coreclr,yizhang82/coreclr,cmckinsey/coreclr,tijoytom/coreclr,Dmitry-Me/coreclr,poizan42/coreclr,jamesqo/coreclr,AlexGhiondea/coreclr,krytarowski/coreclr,pgavlin/coreclr,ragmani/coreclr,yeaicc/coreclr,ramarag/coreclr,wateret/coreclr,Dmitry-Me/coreclr,dasMulli/coreclr,bartdesmet/coreclr,pgavlin/coreclr,poizan42/coreclr,cmckinsey/coreclr,hseok-oh/coreclr,tijoytom/coreclr,sagood/coreclr,wtgodbe/coreclr,James-Ko/coreclr,wtgodbe/coreclr,qiudesong/coreclr,botaberg/coreclr,dasMulli/coreclr,botaberg/coreclr,gkhanna79/coreclr,YongseopKim/coreclr,dasMulli/coreclr,bartdesmet/coreclr,gkhanna79/coreclr,dpodder/coreclr,AlexGhiondea/coreclr,neurospeech/coreclr,mmitche/coreclr,jamesqo/coreclr,Dmitry-Me/coreclr,naamunds/coreclr,russellhadley/coreclr,cydhaselton/coreclr,krk/coreclr,wateret/coreclr,mmitche/coreclr,bartdesmet/coreclr,ragmani/coreclr,yeaicc/coreclr,cshung/coreclr,sjsinju/coreclr,gkhanna79/coreclr,qiudesong/coreclr,YongseopKim/coreclr,hseok-oh/coreclr,cmckinsey/coreclr,dpodder/coreclr,yeaicc/coreclr,JosephTremoulet/coreclr,cshung/coreclr,hseok-oh/coreclr,wtgodbe/coreclr,kyulee1/coreclr,wateret/coreclr,rartemev/coreclr,AlexGhiondea/coreclr,mskvortsov/coreclr,parjong/coreclr,mskvortsov/coreclr,sagood/coreclr,alexperovich/coreclr,krytarowski/coreclr,botaberg/coreclr,neurospeech/coreclr,sjsinju/coreclr,kyulee1/coreclr,sagood/coreclr,ragmani/coreclr,rartemev/coreclr,kyulee1/coreclr,alexperovich/coreclr,jamesqo/coreclr,kyulee1/coreclr,sjsinju/coreclr,ramarag/coreclr,sagood/coreclr,sagood/coreclr,dasMulli/coreclr,parjong/coreclr,yizhang82/coreclr,pgavlin/coreclr,yeaicc/coreclr,cshung/coreclr,Dmitry-Me/coreclr,ragmani/coreclr,parjong/coreclr,pgavlin/coreclr,mskvortsov/coreclr,gkhanna79/coreclr,neurospeech/coreclr,wtgodbe/coreclr,cydhaselton/coreclr,gkhanna79/coreclr,ramarag/coreclr,ruben-ayrapetyan/coreclr,ruben-ayrapetyan/coreclr,jamesqo/coreclr,JonHanna/coreclr,ramarag/coreclr,ruben-ayrapetyan/coreclr,mmitche/coreclr,JonHanna/coreclr,krk/coreclr,jamesqo/coreclr,wtgodbe/coreclr,kyulee1/coreclr,JonHanna/coreclr,naamunds/coreclr,James-Ko/coreclr,pgavlin/coreclr,qiudesong/coreclr,dpodder/coreclr,James-Ko/coreclr,mskvortsov/coreclr,hseok-oh/coreclr,JonHanna/coreclr,rartemev/coreclr,YongseopKim/coreclr,poizan42/coreclr,alexperovich/coreclr,dasMulli/coreclr,dasMulli/coreclr,krytarowski/coreclr,yeaicc/coreclr,tijoytom/coreclr,YongseopKim/coreclr,JosephTremoulet/coreclr,alexperovich/coreclr,botaberg/coreclr,sjsinju/coreclr,AlexGhiondea/coreclr,tijoytom/coreclr,yizhang82/coreclr,rartemev/coreclr,jhendrixMSFT/coreclr,krk/coreclr,wateret/coreclr,naamunds/coreclr,cmckinsey/coreclr,parjong/coreclr,qiudesong/coreclr,jhendrixMSFT/coreclr,bartdesmet/coreclr,naamunds/coreclr,yizhang82/coreclr,JonHanna/coreclr,James-Ko/coreclr,neurospeech/coreclr,yeaicc/coreclr,ragmani/coreclr,dpodder/coreclr,poizan42/coreclr,ruben-ayrapetyan/coreclr,yizhang82/coreclr,russellhadley/coreclr,mmitche/coreclr,sjsinju/coreclr,bartdesmet/coreclr,parjong/coreclr,botaberg/coreclr,yeaicc/coreclr,yizhang82/coreclr,mskvortsov/coreclr,rartemev/coreclr,gkhanna79/coreclr,alexperovich/coreclr,russellhadley/coreclr,krytarowski/coreclr,qiudesong/coreclr,Dmitry-Me/coreclr,ruben-ayrapetyan/coreclr,sjsinju/coreclr,jhendrixMSFT/coreclr,jhendrixMSFT/coreclr,ragmani/coreclr,ramarag/coreclr,russellhadley/coreclr,dasMulli/coreclr,hseok-oh/coreclr,pgavlin/coreclr,sagood/coreclr,cydhaselton/coreclr,botaberg/coreclr,YongseopKim/coreclr,mmitche/coreclr,cshung/coreclr,wtgodbe/coreclr,dpodder/coreclr,russellhadley/coreclr,bartdesmet/coreclr,ramarag/coreclr,jhendrixMSFT/coreclr