optimizations flags that are equivalent to -O3

Little little369@gmail.com
Sun Feb 14 22:34:00 GMT 2010


Hi,

According to GCC 4.3.3 manuals, -O3 turns on the following optimization
flags. However, I tested with 4.5.0 snapshot, -O3 produced a binary 3x
faster than the one produced by the following optimization flags. It seems
-O3 turns on optimization flags that are not in the following list. Any
info... Thanks.



-fauto-inc-dec 
-fcprop-registers 
-fdce 
-fdefer-pop 
-fdelayed-branch 
-fdse 
-fguess-branch-probability 
-fif-conversion2 
-fif-conversion 
-finline-small-functions 
-fipa-pure-const 
-fipa-reference 
-fmerge-constants
-fsplit-wide-types 
-ftree-builtin-call-dce 
-ftree-ccp 
-ftree-ch 
-ftree-copyrename 
-ftree-dce 
-ftree-dominator-opts 
-ftree-dse 
-ftree-fre 
-ftree-sra 
-ftree-ter 
-funit-at-a-time
-fthread-jumps 
-falign-functions  -falign-jumps 
-falign-loops  -falign-labels 
-fcaller-saves 
-fcrossjumping 
-fcse-follow-jumps  -fcse-skip-blocks 
-fdelete-null-pointer-checks 
-fexpensive-optimizations 
-fgcse  -fgcse-lm  
-findirect-inlining 
-foptimize-sibling-calls 
-fpeephole2 
-fregmove 
-freorder-blocks  -freorder-functions 
-frerun-cse-after-loop  
-fsched-interblock  -fsched-spec 
-fschedule-insns  -fschedule-insns2 
-fstrict-aliasing -fstrict-overflow 
-ftree-switch-conversion 
-ftree-pre 
-ftree-vrp
-ffinline-functions
-funswitch-loops
-fpredictive-commoning
-fgcse-after-reload
-ftree-vectorize 


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