5.7.7.9 Align-loops Option

The -falign-loops=n option aligns loops to the next power of two greater than n. For instance, -falign-loops=32 aligns loops to the next 32-byte boundary; -falign-loops=24 aligns loops to the next 32-byte boundary but only if this can be done by skipping no more than 23 bytes.

The -fno-align-loops form of this option is equivalent to -falign-loops=1, which implies that the loop is not aligned. If n is not specified or is zero, a default of alignment of 1 byte is used, which implies that the loop is not aligned. If n is not a power of 2, the alignment value is rounded up.

For instance, -falign-loops=32 aligns loops to the next 32-byte boundary; -falign-loops=24 aligns loops to the next 32-byte boundary but only if this can be done by skipping no more than 23 bytes.

If the loops are executed many times, this makes up for any execution of the dummy padding instructions.

If the alignment values specified by -falign-labels is greater than that specified with this option, then its value is used to align loops instead.