ppc_unroll_speculative

Controls speculative unrolling of counting loops which do not have fixed counts.

#pragma ppc_unroll_speculative on | off
  

The compiler uses the value specified with the ppc_unroll_factor_limit pragma to compute how many times to unroll eligible loops. The compiler adjusts the value specified with ppc_unroll_factor_limit so that it is equal to or less than the closest power of 2.

This optimization is only applied when:

• loop unrolling is turned on with the opt_unroll_loops pragma
• the loop iterator is a 32-bit value ( int , long , unsigned int , unsigned long )
• the loop's body has no conditional statements

If you enable this pragma, the loop unrolling factor is a power of 2, less than or equal to the value specified by the ppc_unroll_factor_limit pragma.

The opt_unroll_loops pragma controls all loop unrolling optimization. To check this setting, use __option (ppc_unroll_speculative) . By default, this pragma is on when loop unrolling is enabled.