[clang] [AArch64][SME2] Add PEXT, PSEL builtins for SME2 (PR #72827)

[Sander de Smalen via cfe-commits]

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@@ -5,6 +5,11 @@
 // RUN: %clang_cc1 -fclang-abi-compat=latest -triple aarch64-none-linux-gnu \
 // RUN:   -target-feature +sve2p1 -S -O1 -Werror -emit-llvm -o - -x c++ %s | FileCheck %s -check-prefix=CPP-CHECK
 // RUN: %clang_cc1 -fclang-abi-compat=latest -triple aarch64-none-linux-gnu -target-feature +sve2p1 -S -disable-O0-optnone -Werror -Wall -o /dev/null %s
+// RUN: %clang_cc1 -fclang-abi-compat=latest -triple aarch64-none-linux-gnu \
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sdesmalen-arm wrote:

> should this be __arm_streaming_compatible instead of __arm_streaming for psel

Yes. It is possible to add `__arm_streaming_compatible` to all the functions below, since this attribute keyword does not require `+sme`.

https://github.com/llvm/llvm-project/pull/72827