[llvm] Adding the support for vectorization of loops with load based tripcount (PR #209390)

[Ramkumar Ramachandra via llvm-commits]

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@@ -0,0 +1,35 @@
+; RUN: opt < %s -passes=loop-vectorize -enable-vectorize-loads-as-bound -force-vector-width=4 -force-vector-interleave=1 -S | FileCheck %s
+;
+; Negative test: the exit condition is an fcmp (not icmp). 
+; SCEV cannot compute the trip count of a float-bounded loop, so the
+; pass enters the dynamic-bound path.  It then rejects because the
+; branch condition is an FCmpInst, not an ICmpInst.
+;
+;   void foo(float *A, float *B, float *Limit) {
+;     for (float x = 0.0f; x < *Limit; x += 1.0f)
+;       A[(int)x] = B[(int)x];
+;   }
+
+define void @foo(ptr %A, ptr %B, ptr %Limit) {
+; CHECK-LABEL: @foo(
+; CHECK-NOT:   vector.body
+; CHECK-NOT:   .bound.pre
+entry:
+  br label %for.body
+
+for.body:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %for.body ]
+  %fiv = phi float [ 0.0, %entry ], [ %fiv.next, %for.body ]
+  %gep.b = getelementptr inbounds i32, ptr %B, i64 %iv
+  %b = load i32, ptr %gep.b, align 4
+  %gep.a = getelementptr inbounds i32, ptr %A, i64 %iv
+  store i32 %b, ptr %gep.a, align 4
+  %iv.next = add nuw nsw i64 %iv, 1
+  %fiv.next = fadd float %fiv, 1.0
+  %lim = load float, ptr %Limit, align 4
+  %cmp = fcmp olt float %fiv.next, %lim
+  br i1 %cmp, label %for.body, label %for.exit
+
+for.exit:
----------------
artagnon wrote:

```suggestion
exit:
```

similarly in all tests?

https://github.com/llvm/llvm-project/pull/209390