diff --git a/llvm/include/llvm/IR/Function.h b/llvm/include/llvm/IR/Function.h
--- a/llvm/include/llvm/IR/Function.h
+++ b/llvm/include/llvm/IR/Function.h
@@ -268,6 +268,9 @@
         getContext(), AttributeList::FunctionIndex, Kind));
   }
 
+  /// Check if this function is a coroutine.
+  bool isCoroutine() const { return hasFnAttribute("coroutine.presplit"); }
+
   enum ProfileCountType { PCT_Invalid, PCT_Real, PCT_Synthetic };
 
   /// Class to represent profile counts.
diff --git a/llvm/lib/Analysis/InlineCost.cpp b/llvm/lib/Analysis/InlineCost.cpp
--- a/llvm/lib/Analysis/InlineCost.cpp
+++ b/llvm/lib/Analysis/InlineCost.cpp
@@ -2332,6 +2332,13 @@
   if (!Callee)
     return InlineResult::failure("indirect call");
 
+  // When callee coroutine function is inlined into caller coroutine function
+  // before coro-split pass,
+  // coro-early pass can not handle this quiet well.
+  // So we won't inline the coroutine function if it have not been unsplited
+  if (Callee->isCoroutine())
+    return InlineResult::failure("unsplited coroutine call");
+
   // Never inline calls with byval arguments that does not have the alloca
   // address space. Since byval arguments can be replaced with a copy to an
   // alloca, the inlined code would need to be adjusted to handle that the
diff --git a/llvm/lib/Transforms/IPO/AlwaysInliner.cpp b/llvm/lib/Transforms/IPO/AlwaysInliner.cpp
--- a/llvm/lib/Transforms/IPO/AlwaysInliner.cpp
+++ b/llvm/lib/Transforms/IPO/AlwaysInliner.cpp
@@ -46,7 +46,14 @@
   SmallSetVector<CallBase *, 16> Calls;
   bool Changed = false;
   SmallVector<Function *, 16> InlinedFunctions;
-  for (Function &F : M)
+  for (Function &F : M) {
+    // When callee coroutine function is inlined into caller coroutine function
+    // before coro-split pass,
+    // coro-early pass can not handle this quiet well.
+    // So we won't inline the coroutine function if it have not been unsplited
+    if (F.isCoroutine())
+      continue;
+
     if (!F.isDeclaration() && F.hasFnAttribute(Attribute::AlwaysInline) &&
         isInlineViable(F).isSuccess()) {
       Calls.clear();
@@ -90,6 +97,7 @@
       // invalidation issues while deleting functions.
       InlinedFunctions.push_back(&F);
     }
+  }
 
   // Remove any live functions.
   erase_if(InlinedFunctions, [&](Function *F) {
@@ -182,6 +190,13 @@
   if (!Callee)
     return InlineCost::getNever("indirect call");
 
+  // When callee coroutine function is inlined into caller coroutine function
+  // before coro-split pass,
+  // coro-early pass can not handle this quiet well.
+  // So we won't inline the coroutine function if it have not been unsplited
+  if (Callee->isCoroutine())
+    return InlineCost::getNever("unsplited coroutine call");
+
   // FIXME: We shouldn't even get here for declarations.
   if (Callee->isDeclaration())
     return InlineCost::getNever("no definition");
diff --git a/llvm/test/Transforms/Coroutines/coro-inline.ll b/llvm/test/Transforms/Coroutines/coro-inline.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Transforms/Coroutines/coro-inline.ll
@@ -0,0 +1,43 @@
+; RUN: opt < %s -always-inline -barrier -coro-early -barrier -coro-split -S | FileCheck %s
+; RUN: opt < %s -enable-new-pm  -always-inline -coro-early -coro-split  -S | FileCheck %s
+; RUN: opt < %s -sample-profile-file=%S/Inputs/sample.text.prof -pgo-kind=pgo-sample-use-pipeline -coro-early -barrier -sample-profile -barrier -coro-split  -disable-inlining=true -S | FileCheck %s
+; RUN: opt < %s -enable-new-pm -sample-profile-file=%S/Inputs/sample.text.prof -pgo-kind=pgo-sample-use-pipeline -coro-early -sample-profile -coro-split  -disable-inlining=true -S | FileCheck %s
+
+; Function Attrs: alwaysinline ssp uwtable
+define void @ff() #0 !dbg !12 {
+entry:
+  %id = call token @llvm.coro.id(i32 16, i8* null, i8* null, i8* null)
+  %begin = call i8* @llvm.coro.begin(token %id, i8* null)
+  ret void
+}
+
+; CHECK:  call void @ff()
+; Function Attrs: alwaysinline ssp uwtable
+define void @foo() #0 !dbg !8 {
+entry:
+  %id1 = call token @llvm.coro.id(i32 16, i8* null, i8* null, i8* null)
+  %begin = call i8* @llvm.coro.begin(token %id1, i8* null)
+  call void @ff(), !dbg !11
+  ret void
+}
+
+declare token @llvm.coro.id(i32, i8* readnone, i8* nocapture readonly, i8*)
+declare i8* @llvm.coro.begin(token, i8* writeonly)
+
+attributes #0 = { alwaysinline ssp uwtable "coroutine.presplit"="1" "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="penryn" "target-features"="+cx16,+cx8,+fxsr,+mmx,+sahf,+sse,+sse2,+sse3,+sse4.1,+ssse3,+x87" "unsafe-fp-math"="false" "use-sample-profile" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "inline_O2.cpp", directory: "")
+!2 = !{}
+!3 = !{i32 7, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{i32 7, !"PIC Level", i32 2}
+!8 = distinct !DISubprogram(name: "foo", linkageName: "foo", scope: !1, file: !1, line: 46, type: !9, scopeLine: 46, flags: DIFlagPrototyped, unit: !0, retainedNodes: !2)
+!9 = !DISubroutineType(types: !10)
+!10 = !{null}
+!11 = !DILocation(line: 2, column: 0, scope: !8)
+!12 = distinct !DISubprogram(name: "ff", linkageName: "ff", scope: !1, file: !1, line: 46, type: !9, scopeLine: 46, flags: DIFlagPrototyped, unit: !0, retainedNodes: !2)