2 ms·
> We find that, while -O2 has a significant impact relative to -O1, the performance impact of -O3 over -O2 optimizations is indistinguishable from random noise.
by nestorD 8y ago
> We find that, while -O2 has a significant impact relative to -O1, the performance impact of -O3 over -O2 optimizations is indistinguishable from random noise.
- gnufx 8y agoThat's definitely not true generally for GCC on floating point computation. O3 gets you vectorization, especially with -ffast-math (and extra loop optimizations recently). That's not to say it's always faster, of course; measure, as ever.