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| author | yaozhongxiao <yaozhongxiao@linux.alibaba.com> | 2021-02-03 15:49:30 +0000 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2021-02-03 15:49:30 +0000 |
| commit | 598876574184e745defee4b36dc2408068b7a22e (patch) | |
| tree | ec9e5db823dea825e16f10418c11a0bd8c697d43 /gcc/tree-loop-distribution.c | |
| parent | 3de9bd16c91c5fc050961db6887880b303b3a630 (diff) | |
| download | gcc-598876574184e745defee4b36dc2408068b7a22e.zip gcc-598876574184e745defee4b36dc2408068b7a22e.tar.gz gcc-598876574184e745defee4b36dc2408068b7a22e.tar.bz2 | |
libstdc++: Improve "find_first/last_set" for NEON
The find_first_set and find_last_set method is not optimal for neon, it
needs to be improved by synthesized with horizontal adds(vaddv) which
will reduce the generated assembly code. In the following cases,
vaddvq_s16 will generate 2 instructions but vpadd_s16 will generate 4
instructions:
# vaddvq_s16
vaddvq_s16(__asint);
// addv h0, v1.8h
// smov w1, v0.h[0]
# vpadd_s16
vpaddq_s16(vpaddq_s16(vpaddq_s16(__asint, __zero), __zero), __zero)[0]
// addp v1.8h,v1.8h,v2.8h
// addp v1.8h,v1.8h,v2.8h
// addp v1.8h,v1.8h,v2.8h
// smov w1, v1.h[0]
#
libstdc++-v3/ChangeLog:
* include/experimental/bits/simd_neon.h: Replace repeated vpadd
calls with a single vaddv for aarch64.
Diffstat (limited to 'gcc/tree-loop-distribution.c')
0 files changed, 0 insertions, 0 deletions