gnu /
gcc /
d0889b5d37ff40149b44e3c7d82f693d430cd891 aarch64: Model zero-high-half semantics of [SU]QXTN instructions
Split the aarch64_<su>qmovn<mode> pattern into separate scalar and
vector variants. Further split the vector RTL pattern into big/
little endian variants that model the zero-high-half semantics of the
underlying instruction. Modeling these semantics allows for better
RTL combinations while also removing some register allocation issues
as the compiler now knows that the operation is totally destructive.
Add new tests to narrow_zero_high_half.c to verify the benefit of
this change.
gcc/ChangeLog:
2021-06-14 Jonathan Wright <jonathan.wright@arm.com>
* config/aarch64/aarch64-simd-builtins.def: Split generator
for aarch64_<su>qmovn builtins into scalar and vector
variants.
* config/aarch64/aarch64-simd.md (aarch64_<su>qmovn<mode>_insn_le):
Define.
(aarch64_<su>qmovn<mode>_insn_be): Define.
(aarch64_<su>qmovn<mode>): Split into scalar and vector
variants. Change vector variant to an expander that emits the
correct instruction depending on endianness.
gcc/testsuite/ChangeLog:
* gcc.target/aarch64/narrow_zero_high_half.c: Add new tests.
3 files changed
