[llvm] [ARM][SLP] Fix cost function for SLP Vectorization of ZExt/SExt (PR #122713)

[David Green via llvm-commits]

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+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -passes="default<O1>,slp-vectorizer" --mtriple arm-none-eabi -mattr=+mve -S -o - | FileCheck %s
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davemgreen wrote:

The tests look useful on their own for SLP. Can you alter them to not require -O1? Ideally the SLP vectorizer tests just run the SLP pass on its own, so it is not dependant on the rest of the pipeline. If you want to test the whole pipeline then they can be added to PhaseOrdering tests.

https://github.com/llvm/llvm-project/pull/122713