Analyzing Optimization: What's New in 3.4?

Andrew Pinski pinskia@physics.uc.edu
Tue Aug 12 06:08:00 GMT 2003


On Monday, Aug 11, 2003, at 19:09 US/Eastern, Scott Robert Ladd wrote:
>
> I'm compiling with -O1 and enabling specific flags to compare 
> interactions and generated code performance; I've already added 
> -funit-at-a-time to the mix.

If you are doing that, then add these (all by looking at the file 
gcc/opts.c (537-583).
-frename-registers (enabled at -O3)
-funswitch-loops (enabled at -O3)
-finline-functions (enabled at -O3)
-fstrength-reduce (enabled at -O2)
-fcaller-saves (enabled at -O2)
-fpeephole2  (enabled at -O2)
-fstrict-aliasing  (enabled at -O2)
-fregmove  (enabled at -O2)
-freorder-blocks  (enabled at -O2)
-freoder-functions (enabled at -O2)
-fschedule-insn (enabled at -O2)
-fschedule-insn2 (enabled at -O2)
-fgcse (enabled at -O2)
-fepensive-optimizations (enabled at -O2)
-falign-loops (enabled at -O2)
-falign-jumps (enabled at -O2)
-falign-functions (enabled at -O2)


Thanks,
Andrew Pinski



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