Hi, Version 2 of the patch adds tests to verify the benefit of this change.
Ok for master? Thanks, Jonathan --- gcc/ChangeLog: 2021-06-14 Jonathan Wright <jonathan.wri...@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. From: Gcc-patches <gcc-patches-bounces+jonathan.wright=arm....@gcc.gnu.org> on behalf of Jonathan Wright via Gcc-patches <gcc-patches@gcc.gnu.org> Sent: 15 June 2021 10:59 To: gcc-patches@gcc.gnu.org <gcc-patches@gcc.gnu.org> Subject: [PATCH] aarch64: Model zero-high-half semantics of [SU]QXTN instructions Hi, As subject, this patch first splits the aarch64_<su>qmovn<mode> pattern into separate scalar and vector variants. It then further splits 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. Regression tested and bootstrapped on aarch64-none-linux-gnu - no issues. Ok for master? Thanks, Jonathan --- gcc/ChangeLog: 2021-06-14 Jonathan Wright <jonathan.wri...@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.
rb14565.patch
Description: rb14565.patch