According to the Neoverse V2 Software Optimization Guide (section 4.14), the instruction pairs CMP+CSEL and CMP+CSET can be fused, which had not been implemented so far. This patch implements and tests the two fusion pairs.
The patch was bootstrapped and regtested on aarch64-linux-gnu, no regression.
There was also no non-noise impact on SPEC CPU2017 benchmark.
OK for mainline?
Signed-off-by: Jennifer Schmitz <jschm...@nvidia.com>
gcc/
* config/aarch64/aarch64.cc (aarch_macro_fusion_pair_p): Implement
fusion logic.
* config/aarch64/aarch64-fusion-pairs.def (cmp+csel): New entry.
(cmp+cset): Likewise.
* config/aarch64/tuning_models/neoversev2.h: Enable logic in
field fusible_ops.
gcc/testsuite/
* gcc.target/aarch64/fuse_cmp_csel.c: New test.
* gcc.target/aarch64/fuse_cmp_cset.c: Likewise.
0001-aarch64-Fuse-CMP-CSEL-and-CMP-CSET-for-mcpu-neoverse.patch
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