1 files changed, 118 insertions, 0 deletions
diff --git a/test/Analysis/LoopDependenceAnalysis/siv-weak-crossing.ll b/test/Analysis/LoopDependenceAnalysis/siv-weak-crossing.ll
new file mode 100644
index 0000000000000..3d9f2583b3abf
--- /dev/null
+++ b/test/Analysis/LoopDependenceAnalysis/siv-weak-crossing.ll
@@ -0,0 +1,118 @@
+; RUN: opt < %s -disable-output -analyze -lda | FileCheck %s
+
+@x = common global [256 x i32] zeroinitializer, align 4
+@y = common global [256 x i32] zeroinitializer, align 4
+
+;; for (i = 0; i < 256; i++)
+;;   x[i] = x[255 - i] + y[i]
+
+define void @f1(...) nounwind {
+entry:
+  br label %for.body
+
+for.body:
+  %i = phi i64 [ 0, %entry ], [ %i.next, %for.body ]
+  %i.255 = sub i64 255, %i
+  %y.ld.addr = getelementptr [256 x i32]* @y, i64 0, i64 %i
+  %x.ld.addr = getelementptr [256 x i32]* @x, i64 0, i64 %i.255
+  %x.st.addr = getelementptr [256 x i32]* @x, i64 0, i64 %i
+  %x = load i32* %x.ld.addr     ; 0
+  %y = load i32* %y.ld.addr     ; 1
+  %r = add i32 %y, %x
+  store i32 %r, i32* %x.st.addr ; 2
+; CHECK: 0,2: dep
+; CHECK: 1,2: ind
+  %i.next = add i64 %i, 1
+  %exitcond = icmp eq i64 %i.next, 256
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}
+
+;; for (i = 0; i < 100; i++)
+;;   x[i] = x[255 - i] + y[i]
+
+define void @f2(...) nounwind {
+entry:
+  br label %for.body
+
+for.body:
+  %i = phi i64 [ 0, %entry ], [ %i.next, %for.body ]
+  %i.255 = sub i64 255, %i
+  %y.ld.addr = getelementptr [256 x i32]* @y, i64 0, i64 %i
+  %x.ld.addr = getelementptr [256 x i32]* @x, i64 0, i64 %i.255
+  %x.st.addr = getelementptr [256 x i32]* @x, i64 0, i64 %i
+  %x = load i32* %x.ld.addr     ; 0
+  %y = load i32* %y.ld.addr     ; 1
+  %r = add i32 %y, %x
+  store i32 %r, i32* %x.st.addr ; 2
+; CHECK: 0,2: dep
+; CHECK: 1,2: ind
+  %i.next = add i64 %i, 1
+  %exitcond = icmp eq i64 %i.next, 100
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}
+
+;; // the first iteration (i=0) leads to an out-of-bounds access of x. as the
+;; // result of this access is undefined, _any_ dependence result is safe.
+;; for (i = 0; i < 256; i++)
+;;   x[i] = x[256 - i] + y[i]
+
+define void @f3(...) nounwind {
+entry:
+  br label %for.body
+
+for.body:
+  %i = phi i64 [ 0, %entry ], [ %i.next, %for.body ]
+  %i.256 = sub i64 0, %i
+  %y.ld.addr = getelementptr [256 x i32]* @y, i64 0, i64 %i
+  %x.ld.addr = getelementptr [256 x i32]* @x, i64 1, i64 %i.256
+  %x.st.addr = getelementptr [256 x i32]* @x, i64 0, i64 %i
+  %x = load i32* %x.ld.addr     ; 0
+  %y = load i32* %y.ld.addr     ; 1
+  %r = add i32 %y, %x
+  store i32 %r, i32* %x.st.addr ; 2
+; CHECK: 0,2: dep
+; CHECK: 1,2:
+  %i.next = add i64 %i, 1
+  %exitcond = icmp eq i64 %i.next, 256
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}
+
+;; // slightly contrived but valid IR for the following loop, where all
+;; // accesses in all iterations are within bounds. while this example's first
+;; // (ZIV-)subscript is (0, 1), accesses are dependent.
+;; for (i = 1; i < 256; i++)
+;;   x[i] = x[256 - i] + y[i]
+
+define void @f4(...) nounwind {
+entry:
+  br label %for.body
+
+for.body:
+  %i = phi i64 [ 0, %entry ], [ %i.next, %for.body ]
+  %i.1 = add i64 1, %i
+  %i.256 = sub i64 -1, %i
+  %y.ld.addr = getelementptr [256 x i32]* @y, i64 0, i64 %i.1
+  %x.ld.addr = getelementptr [256 x i32]* @x, i64 1, i64 %i.256
+  %x.st.addr = getelementptr [256 x i32]* @x, i64 0, i64 %i.1
+  %x = load i32* %x.ld.addr     ; 0
+  %y = load i32* %y.ld.addr     ; 1
+  %r = add i32 %y, %x
+  store i32 %r, i32* %x.st.addr ; 2
+; CHECK: 0,2: dep
+; CHECK: 1,2: ind
+  %i.next = add i64 %i, 1
+  %exitcond = icmp eq i64 %i.next, 256
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}