* optimizations flags that are equivalent to -O3
@ 2010-02-14 22:34 Little
2010-02-15 9:14 ` Nicholas Sherlock
0 siblings, 1 reply; 2+ messages in thread
From: Little @ 2010-02-14 22:34 UTC (permalink / raw)
To: gcc-help
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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* Re: optimizations flags that are equivalent to -O3
2010-02-14 22:34 optimizations flags that are equivalent to -O3 Little
@ 2010-02-15 9:14 ` Nicholas Sherlock
0 siblings, 0 replies; 2+ messages in thread
From: Nicholas Sherlock @ 2010-02-15 9:14 UTC (permalink / raw)
To: gcc-help
On 15/02/2010 9:27 a.m., Little wrote:
> It seems
> -O3 turns on optimization flags that are not in the following list. Any
> info... Thanks.
Yes, that's correct. There are optimizations for which no flags exist
and the only way of controlling them is with the -O flag.
Cheers,
Nicholas Sherlock
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2010-02-14 22:34 optimizations flags that are equivalent to -O3 Little
2010-02-15 9:14 ` Nicholas Sherlock
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