--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/tailcall-assume-xbb.ll	Mon May 25 11:55:54 2020 +0900
@@ -0,0 +1,48 @@
+; RUN: opt -codegenprepare -S -mtriple=x86_64-linux < %s | FileCheck %s
+
+; The ret instruction can be duplicated into BB case2 even though there is an
+; intermediate BB exit1 and call to llvm.assume.
+
+@ptr = external global i8*, align 8
+
+; CHECK:       %ret1 = tail call i8* @qux()
+; CHECK-NEXT:  ret i8* %ret1
+
+; CHECK:       %ret2 = tail call i8* @bar()
+; CHECK-NEXT:  ret i8* %ret2
+
+define i8* @foo(i64 %size, i64 %v1, i64 %v2) {
+entry:
+  %cmp1 = icmp ult i64 %size, 1025
+  br i1 %cmp1, label %if.end, label %case1
+
+case1:
+  %ret1 = tail call i8* @qux()
+  br label %exit2
+
+if.end:
+  %cmp2 = icmp ult i64 %v1, %v2
+  br i1 %cmp2, label %case3, label %case2
+
+case2:
+  %ret2 = tail call i8* @bar()
+  br label %exit1
+
+case3:
+  %ret3 = load i8*, i8** @ptr, align 8
+  br label %exit1
+
+exit1:
+  %retval1 = phi i8* [ %ret2, %case2 ], [ %ret3, %case3 ]
+  %cmp3 = icmp ne i8* %retval1, null
+  tail call void @llvm.assume(i1 %cmp3)
+  br label %exit2
+
+exit2:
+  %retval2 = phi i8* [ %ret1, %case1 ], [ %retval1, %exit1 ]
+  ret i8* %retval2
+}
+
+declare void @llvm.assume(i1)
+declare i8* @qux()
+declare i8* @bar()