[llvm] [LV] Prevent query the computeCost() when VF=1 in emitInvalidCostRemarks(). (PR #117288)

[Elvis Wang 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 -mtriple=riscv64 -mattr=+v -p loop-vectorize -pass-remarks-analysis=loop-vectorize -S | FileCheck %s
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ElvisWang123 wrote:

Passing `-pass-remarks-analysis=loop-vectorize` just for  triggering  `emitInvalidCostRemarks()` and  make sure the compiler don't crash. I don't have any ideas about testing the remark output.

Something I can imagine is that using  `--debug-only=loop-vecotorize` to print the cost. But it always using the legacy cost model to calculate/print the scalar cost.

Do you have better suggestion to test this case?  

https://github.com/llvm/llvm-project/pull/117288