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r242383 - in /trunk/gcc: ChangeLog config/aarch...
- From: wilco at gcc dot gnu dot org
- To: gcc-cvs at gcc dot gnu dot org
- Date: Mon, 14 Nov 2016 11:51:33 -0000
- Subject: r242383 - in /trunk/gcc: ChangeLog config/aarch...
Date: Mon Nov 14 11:51:33 2016
New Revision: 242383
The existing vector costs stop some beneficial vectorization. This is mostly
due to vector statement cost being set to 3 as well as vector loads having a
higher cost than scalar loads. This means that even when we vectorize 4x, it
is possible that the cost of a vectorized loop is similar to the scalar
version, and we fail to vectorize.
Using a cost of 3 for a vector operation suggests they are 3 times as
expensive as scalar operations. Since most vector operations have a
similar throughput as scalar operations, this is not correct.
Using slightly lower values for these heuristics now allows this loop
and many others to be vectorized. On a proprietary benchmark the gain
from vectorizing this loop is around 15-30% which shows vectorizing it is
* config/aarch64/aarch64.c (cortexa57_vector_cost):
Change vec_stmt_cost, vec_align_load_cost and vec_unalign_load_cost.