[llvm] [LoopVectorizer] Add support for partial reductions (PR #92418)

[Eli Friedman via llvm-commits]

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@@ -0,0 +1,100 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
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efriedma-quic wrote:

Please precommit the test, so the difference in the generated code is visible

https://github.com/llvm/llvm-project/pull/92418