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

[Mel Chen via llvm-commits]

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@@ -0,0 +1,86 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=loop-vectorize -force-vector-width=4 -S %s | FileCheck %s --check-prefix=CHECK-REV-MIN
+
+; This test case is extracted from rnflow (fortran) benchmark in polyhedron benchmark suite.
+; The function minlst primarily takes two indices (i.e. range), scans backwards in the range
+; and returns the firstIV of the minimum value.
+
+define fastcc i32 @minlst(i32 %first_index, i32 %last_index, ptr %array) {
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Mel-Chen wrote:

Do we really need `fastcc`?

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