Setting the Environment
Turns off all optimization. Same as
Default. Turns off all optimization.
Decreases code size with some increase in speed.
Optimizes code for minimum size.
Default. Favors speed optimization with some increase in code size. Intrinsics, loop unrolling, and inlining are performed.
Optimizes code for maximum speed.
-O2optimizations plus more aggressive optimizations, such as prefetching, scalar replacement, and loop and memory access transformations.