[MicroBenchmark,LoopInterleaving] Check performance impact of Loop Interleaving Count with varying loop iterations (#26)

* [MicroBenchmarks,LoopInterleaving] Check performance impact of Loop Interleaving Count with varying loop iterations.

This microbenchmark attempts to find the impact of loop interleaving count for different types of loops (big or small, with or without reductions inside them) over different vectorization factors for varying loop trip counts.
Note: Interleaving count of 1 means interleaving is disabled.

These microbenchmarks are to help guide changes in loop interleaving count computation and removal of trip count threshold for interleaving loops in llvm/llvm-project#67725 & related patches.

Author: nilanjana87

MicroBenchmarks/LoopVectorization/CMakeLists.txt

@@ -17,3 +17,12 @@ llvm_test_executable(LoopVectorizationBenchmarks
 )
 
 target_link_libraries(LoopVectorizationBenchmarks benchmark)
+
+llvm_test_run()
+
+llvm_test_executable(LoopInterleavingBenchmarks
+  main.cpp
+  LoopInterleaving.cpp
+)
+
+target_link_libraries(LoopInterleavingBenchmarks benchmark)