[llvm] [LoopVectorize] Vectorize select-cmp reduction pattern for increasing integer induction variable (PR #67812)

[Mel Chen via llvm-commits]

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@@ -1,10 +1,193 @@
-; RUN: opt -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S < %s | FileCheck %s --check-prefix=CHECK
-; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=4 -S < %s | FileCheck %s --check-prefix=CHECK
-; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=1 -S < %s | FileCheck %s --check-prefix=CHECK
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3
+; RUN: opt -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S < %s | FileCheck %s --check-prefix=CHECK-VF4IC1 --check-prefix=CHECK
+; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=4 -S < %s | FileCheck %s --check-prefix=CHECK-VF4IC4 --check-prefix=CHECK
+; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=1 -S < %s | FileCheck %s --check-prefix=CHECK-VF1IC4 --check-prefix=CHECK
 
 define i64 @select_icmp_const_1(ptr %a, i64 %n) {
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Mel-Chen wrote:

They are indeed quite similar. iv-select-cmp.ll is for testing IR generation, including the case of UF > 1. iv-select-cmp-no-wrap.ll is for testing whether vectorization is legal. 
My suggestion is to remove `select_icmp_nuw_nsw` from iv-select-cmp-no-wrap.ll, and retain `@select_icmp_const_1` and `@select_icmp_const_2`.
What do you think?


https://github.com/llvm/llvm-project/pull/67812