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-rw-r--r--gcc/tree-ssa-loop-prefetch.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/gcc/tree-ssa-loop-prefetch.c b/gcc/tree-ssa-loop-prefetch.c
index 9ccf72e..705ee81 100644
--- a/gcc/tree-ssa-loop-prefetch.c
+++ b/gcc/tree-ssa-loop-prefetch.c
@@ -228,13 +228,13 @@ struct mem_ref_group
/* 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. */