[llvm] [LoopVectorize] Add test case for minloc reduction (PR #141556)

[David Sherwood via llvm-commits]

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+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=loop-vectorize -force-vector-width=1 -force-vector-interleave=4 -S %s | FileCheck %s --check-prefix=CHECK-REV-MIN-VW1-IL4
+; RUN: opt -passes=loop-vectorize -force-vector-width=4 -force-vector-interleave=1 -S %s | FileCheck %s --check-prefix=CHECK-REV-MIN-VW4-IL1
+; RUN: opt -passes=loop-vectorize -force-vector-width=4 -force-vector-interleave=2 -S %s | FileCheck %s --check-prefix=CHECK-REV-MIN-VW4-IL2
+
+; This test case is extracted from rnflow (fortran) benchmark in polyhedron benchmark suite.
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david-arm wrote:

Is this testing a common pattern from Fortran, i.e. minloc that looks for the location of the minimum value in an array? I just want to understand if this is something very common to Fortran in general, or for one very specific case in a particular benchmark? If it's the former, then I think it makes sense to create more general, hand-written tests that demonstrate minloc in a variety of situations, i.e. different array types, etc.

https://github.com/llvm/llvm-project/pull/141556