Allow scalar evolution to compute iteration counts for loops with a

pointer-based condition.  This fixes PR3171.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71354 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 27 insertions, 0 deletions

diff --git a/test/Analysis/ScalarEvolution/2009-05-09-PointerEdgeCount.ll b/test/Analysis/ScalarEvolution/2009-05-09-PointerEdgeCount.ll
new file mode 100644
index 0000000..bea46a7
--- /dev/null
+++ b/test/Analysis/ScalarEvolution/2009-05-09-PointerEdgeCount.ll
@@ -0,0 +1,27 @@
+; RUN: llvm-as < %s | opt -analyze -scalar-evolution | grep {count is 2}
+; PR3171
+
+	%struct.Foo = type { i32 }
+	%struct.NonPod = type { [2 x %struct.Foo] }
+
+define void @_Z3foov() nounwind {
+entry:
+	%x = alloca %struct.NonPod, align 8		; <%struct.NonPod*> [#uses=2]
+	%0 = getelementptr %struct.NonPod* %x, i32 0, i32 0		; <[2 x %struct.Foo]*> [#uses=1]
+	%1 = getelementptr [2 x %struct.Foo]* %0, i32 1, i32 0		; <%struct.Foo*> [#uses=1]
+	br label %bb1.i
+
+bb1.i:		; preds = %bb2.i, %entry
+	%.0.i = phi %struct.Foo* [ %1, %entry ], [ %4, %bb2.i ]		; <%struct.Foo*> [#uses=2]
+	%2 = getelementptr %struct.NonPod* %x, i32 0, i32 0, i32 0		; <%struct.Foo*> [#uses=1]
+	%3 = icmp eq %struct.Foo* %.0.i, %2		; <i1> [#uses=1]
+	br i1 %3, label %_ZN6NonPodD1Ev.exit, label %bb2.i
+
+bb2.i:		; preds = %bb1.i
+	%4 = getelementptr %struct.Foo* %.0.i, i32 -1		; <%struct.Foo*> [#uses=1]
+	br label %bb1.i
+
+_ZN6NonPodD1Ev.exit:		; preds = %bb1.i
+	ret void
+}
+