[LoopDist] Add test for missing coverage

Add a testcase to ensure that if we can't find bounds for a necessary
memcheck we don't distribute.

llvm-svn: 244703

diff --git a/llvm/test/Transforms/LoopDistribute/unknown-bounds-for-memchecks.ll b/llvm/test/Transforms/LoopDistribute/unknown-bounds-for-memchecks.ll
new file mode 100644 (file)
index 0000000..2ba746d
--- /dev/null
+++ b/llvm/test/Transforms/LoopDistribute/unknown-bounds-for-memchecks.ll
@@ -0,0 +1,57 @@
+; RUN: opt -basicaa -loop-distribute -S < %s | FileCheck %s
+
+; If we can't find the bounds for one of the arrays in order to generate the
+; memchecks (e.g., C[i * i] below), loop shold not get distributed.
+;
+;   for (i = 0; i < n; i++) {
+;     A[i + 1] = A[i] * 3;
+; -------------------------------
+;     C[i * i] = B[i] * 2;
+;   }
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+
+; Verify that we didn't distribute by checking that we still have the original
+; number of branches.
+
+@A = common global i32* null, align 8
+@B = common global i32* null, align 8
+@C = common global i32* null, align 8
+
+define void @f() {
+entry:
+  %a = load i32*, i32** @A, align 8
+  %b = load i32*, i32** @B, align 8
+  %c = load i32*, i32** @C, align 8
+  br label %for.body
+; CHECK: br
+
+for.body:                                         ; preds = %for.body, %entry
+  %ind = phi i64 [ 0, %entry ], [ %add, %for.body ]
+
+  %arrayidxA = getelementptr inbounds i32, i32* %a, i64 %ind
+  %loadA = load i32, i32* %arrayidxA, align 4
+
+  %mulA = mul i32 %loadA, 3
+
+  %add = add nuw nsw i64 %ind, 1
+  %arrayidxA_plus_4 = getelementptr inbounds i32, i32* %a, i64 %add
+  store i32 %mulA, i32* %arrayidxA_plus_4, align 4
+
+  %arrayidxB = getelementptr inbounds i32, i32* %b, i64 %ind
+  %loadB = load i32, i32* %arrayidxB, align 4
+
+  %mulC = mul i32 %loadB, 2
+
+  %ind_2 = mul i64 %ind, %ind
+  %arrayidxC = getelementptr inbounds i32, i32* %c, i64 %ind_2
+  store i32 %mulC, i32* %arrayidxC, align 4
+
+  %exitcond = icmp eq i64 %add, 20
+  br i1 %exitcond, label %for.end, label %for.body
+; CHECK: br
+; CHECK-NOT: br
+
+for.end:                                          ; preds = %for.body
+  ret void
+}