Fix PR25838.

This is a quick fix to PR25838. The issue comes from the restriction that we
cannot normalize probabilities containing both known and unknown ones. A patch
that removes this restriction is under the review now:

http://reviews.llvm.org/D15548

llvm-svn: 255867
diff --git a/llvm/test/CodeGen/ARM/pr25838.ll b/llvm/test/CodeGen/ARM/pr25838.ll
new file mode 100644
index 0000000..0aa95fd
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/pr25838.ll
@@ -0,0 +1,34 @@
+; RUN: llc < %s
+; PR25838
+
+target triple = "armv7--linux-android"
+
+%0 = type { i32, i32 }
+
+define i32 @foo(%0* readonly) {
+  br i1 undef, label %12, label %2
+
+; <label>:2
+  %3 = trunc i64 undef to i32
+  %4 = icmp eq i32 undef, 0
+  br i1 %4, label %5, label %9
+
+; <label>:5
+  %6 = icmp slt i32 %3, 0
+  %7 = sub nsw i32 0, %3
+  %8 = select i1 %6, i32 %7, i32 %3
+  br label %12
+
+; <label>:9
+  br i1 undef, label %12, label %10
+
+; <label>:10
+  %11 = tail call i32 @bar(i32 undef)
+  unreachable
+
+; <label>:12
+  %13 = phi i32 [ %8, %5 ], [ 0, %1 ], [ undef, %9 ]
+  ret i32 %13
+}
+
+declare i32 @bar(i32)