+2010-06-09 Changpeng Fang <changpeng.fang@amd.com>
+
+ * tree-ssa-loop-prefetch.c (PREFETCH_MOD_TO_UNROLL_FACTOR_RATIO) :
+ Change the PREFETCH_MOD_TO_UNROLL_FACTOR_RATIO threshold value from
+ 8 to 4. Minor change of the related comments.
+
2010-06-09 Sebastian Pop <sebastian.pop@amd.com>
* tree-scalar-evolution.c (instantiate_scev_name): Do not fail
/* Do not generate a prefetch if the unroll factor is significantly less
than what is required by the prefetch. This is to avoid redundant
- prefetches. For example, if prefetch_mod is 16 and unroll_factor is
- 1, this means prefetching requires unrolling the loop 16 times, but
- the loop is not going to be unrolled. In this case (ratio = 16),
+ prefetches. For example, when prefetch_mod is 16 and unroll_factor is
+ 2, prefetching requires unrolling the loop 16 times, but
+ the loop is actually unrolled twice. In this case (ratio = 8),
prefetching is not likely to be beneficial. */
#ifndef PREFETCH_MOD_TO_UNROLL_FACTOR_RATIO
-#define PREFETCH_MOD_TO_UNROLL_FACTOR_RATIO 8
+#define PREFETCH_MOD_TO_UNROLL_FACTOR_RATIO 4
#endif
/* The memory reference. */