High-level Language Optimizations

Option

Description

Default

-ivdep_parallel
Itanium(TM) compiler  only

Indicates there is absolutely no loop-carried memory dependency in the loop where IVDEP directive is specified.

OFF

-prefetch[-]
IA-32 only

Enables or disables prefetch insertion (requires -O3).
Reduces the wait time; optimum use is determined empirically.

-prefetch

-scalar_rep[-]
IA-32 only

Enables (default) or disables scalar replacement performed during loop transformations (requires -O3).
Eliminates all loads and stores of that variable
Increases register pressure.

-scalar_rep

-unroll[n]

n: set maximum number of times to unroll a loop
n omitted: compiler decides whether to perform unrolling or not.
n = 0: disables unroller.
Eliminates some code; hides latencies; can increase code size.
For Itanium-based applications, -unroll[o] is used only for compatibility.

-unroll