Enables or disables loop blocking for the immediately following nested loops. BLOCK_LOOP enables loop blocking for the nested loops. NOBLOCK_LOOP disables loop blocking for the nested loops.
- Can be any of the following:
The clauses can be specified in any order. If you do not specify any clause, the compiler chooses the best blocking factor to apply to all levels of the immediately following nested loop.
- expris a positive scalar constant integer expression representing the blocking factor for the specified loops. This clause is optional. If thefactorclause is not present, the blocking factor will be determined based on processor type and memory access patterns and will be applied to the specified levels in the nested loop following the pragma.At most only onefactorclause can appear in ablock_looppragma.
- level(level_expr[,level_expr]... )
- level_expris specified in the formconst1orconst1:const2whereconst1is a positive integer constantm<= 8 representing the loop at levelm, where the immediate following loop is level 1. Theconst2is a positive integer constantn<= 8 representing the loop at leveln, wheren>m.const1:const2represents the nested loops from levelconst1throughconst2.