[llvm] Add LoopVectorizer support for `llvm.vector.partial.reduce.fadd` (PR #163975)

[Sander de Smalen via llvm-commits]

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@@ -0,0 +1,2740 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --version 6
+; RUN: opt -passes=loop-vectorize -force-vector-interleave=1 -enable-epilogue-vectorization=false -mattr=+sve2p1,+dotprod -S < %s | FileCheck %s --check-prefixes=CHECK-INTERLEAVE1
+; RUN: opt -passes=loop-vectorize -enable-epilogue-vectorization=false -mattr=+sve2p1,+dotprod -S < %s | FileCheck %s --check-prefixes=CHECK-INTERLEAVED
+; RUN: opt -passes=loop-vectorize -force-vector-interleave=1 -vectorizer-maximize-bandwidth -enable-epilogue-vectorization=false -mattr=+sve2p1,+dotprod -S < %s | FileCheck %s --check-prefixes=CHECK-MAXBW
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-none-unknown-elf"
+
+define float @fdotp_f16_f32(ptr %a, ptr %b) #0 {
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sdesmalen-arm wrote:

`attributes #0` are not defined. My suggestoin would be to define it and to add `"target-features"="+sve2p1,+dotprod"`, so that you can remove that from the RUN lines.

also nit: `fdot_f16_f32` (dropping the 'p')

https://github.com/llvm/llvm-project/pull/163975