[llvm] [LoopInterchange] Add tests for the vectorization profitability (NFC) (PR #133665)

[Sjoerd Meijer via llvm-commits]

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@@ -0,0 +1,108 @@
+; RUN: opt < %s -passes=loop-interchange -cache-line-size=64 \
+; RUN:     -pass-remarks-output=%t -disable-output -loop-interchange-profitabilities=vectorize
+; RUN: FileCheck -input-file %t %s
+
+ at A = dso_local global [256 x [256 x float]] zeroinitializer
+ at B = dso_local global [256 x [256 x float]] zeroinitializer
+ at C = dso_local global [256 x [256 x float]] zeroinitializer
+
+; Check that the below loops are exchanged for vectorization.
+;
+; for (int i = 0; i < 256; i++) {
+;   for (int j = 1; j < 256; j++) {
+;     A[i][j] = A[i][j-1] + B[i][j];
+;     C[i][j] += 1;
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sjoerdmeijer wrote:

Just two question about this out of curiousity:
- is the write to array C necessary?
- and is vectorised with a gather/scatter?

https://github.com/llvm/llvm-project/pull/133665