--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/polly/test/ForwardOpTree/noforward_synthesizable_unknownit.ll	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,50 @@
+; RUN: opt %loadPolly -polly-optree -analyze < %s | FileCheck %s -match-full-lines
+;
+; Do not try to forward %i.trunc, it is not synthesizable in %body.
+;
+define void @func(i32 %n, i32* noalias nonnull %A) {
+entry:
+  br label %for
+
+for:
+  %j = phi i32 [0, %entry], [%j.inc, %inc]
+  %j.cmp = icmp slt i32 %j, %n
+  %zero = sext i32 0 to i64
+  br i1 %j.cmp, label %inner.for, label %exit
+
+
+    ; This loop has some unusual properties:
+    ; * It has a known iteration count (8), therefore SCoP-compatible.
+    ; * %i.trunc is synthesizable within the loop ({1,+,1}<%while.body>).
+    ; * %i.trunc is not synthesizable outside of the loop, because its value is
+    ;   unknown when exiting.
+    ;   (should be 8, but ScalarEvolution currently seems unable to derive that)
+    ;
+    ; ScalarEvolution currently seems to not able to handle the %zero.
+    ; If it becomes more intelligent, there might be other such loop constructs.
+    inner.for:
+      %i = phi i64 [%zero, %for], [%i.inc, %inner.for]
+      %i.inc = add nuw nsw i64 %i, 1
+      %i.trunc = trunc i64 %i.inc to i32
+      %i.and = and i32 %i.trunc, 7
+      %inner.cond = icmp eq i32 %i.and, 0
+      br i1 %inner.cond, label %body, label %inner.for
+
+    body:
+      store i32 %i.trunc, i32* %A
+      br label %inc
+
+
+inc:
+  %j.inc = add nuw nsw i32 %j, 1
+  br label %for
+
+exit:
+  br label %return
+
+return:
+  ret void
+}
+
+
+; CHECK: ForwardOpTree executed, but did not modify anything