[llvm] LAA: pre-commit tests for stride-versioning (PR #97570)

[Ramkumar Ramachandra via llvm-commits]

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@@ -310,3 +310,184 @@ loop:
 exit:                                          ; preds = %loop
   ret void
 }
+
+; Check the scenario where we have an unknown Stride, which happens to also be
+; the loop iteration count. If we speculate Stride==1, it implies that the loop
+; will iterate no more than a single iteration.
+define i32 @unknown_stride_equalto_tc(i32 %N, ptr %A, ptr %B, i32 %i, i32 %j)  {
+; CHECK-LABEL: 'unknown_stride_equalto_tc'
+; CHECK-NEXT:    for.body:
+; CHECK-NEXT:      Memory dependences are safe
+; CHECK-NEXT:      Dependences:
+; CHECK-NEXT:      Run-time memory checks:
+; CHECK-NEXT:      Grouped accesses:
+; CHECK-EMPTY:
+; CHECK-NEXT:      Non vectorizable stores to invariant address were not found in loop.
+; CHECK-NEXT:      SCEV assumptions:
+; CHECK-EMPTY:
+; CHECK-NEXT:      Expressions re-written:
+;
+entry:
+  %cmp8 = icmp eq i32 %N, 0
+  br i1 %cmp8, label %for.end, label %for.body.lr.ph
+
+for.body.lr.ph:
+  br label %for.body
+
+for.body:
+  %tmp.010 = phi i32 [ 0, %for.body.lr.ph ], [ %add1, %for.body ]
+  %k.09 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.body ]
+  %mul = mul i32 %k.09, %N
+  %add = add i32 %mul, %j
+  %arrayidx = getelementptr inbounds i16, ptr %B, i32 %add
+  %0 = load i16, ptr %arrayidx, align 2
+  %conv = sext i16 %0 to i32
+  %add1 = add nsw i32 %tmp.010, %conv
----------------
artagnon wrote:

Thanks for catching this! I didn't realize that nothing would be printed when there are no stores. Kindly let me know if the update is good.

https://github.com/llvm/llvm-project/pull/97570