13 Dec
2002
13 Dec
'02
2:20 p.m.
Tristan Scott alug@scott998.freeserve.co.uk writes:
NuTTeR -- Not Entered -- wrote:
I thought that -O3 was a bad thing to do when compiling(it must be good for somthing but i thought -O2 was the safe option)?
Yes -02 is the normal 'safe' option. -03 gives good speed boosts (up to ~10% depending on code) but in the occasional scenario the optimised operation will not do /quite/ what is expected by the programmer.
What semantic changes do you think are implied by -O3? The manual says it turns on -finline-functions and (-frename-registers, which could make debugging at least inconvenient but shouldn't change the actual behaviour of the running code.