Index: llvm/trunk/lib/Transforms/Coroutines/CoroSplit.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Coroutines/CoroSplit.cpp
+++ llvm/trunk/lib/Transforms/Coroutines/CoroSplit.cpp
@@ -777,6 +777,8 @@
 }
 
 static void splitCoroutine(Function &F, CallGraph &CG, CallGraphSCC &SCC) {
+  EliminateUnreachableBlocks(F);
+
   coro::Shape Shape(F);
   if (!Shape.CoroBegin)
     return;
Index: llvm/trunk/test/Transforms/Coroutines/coro-frame-unreachable.ll
===================================================================
--- llvm/trunk/test/Transforms/Coroutines/coro-frame-unreachable.ll
+++ llvm/trunk/test/Transforms/Coroutines/coro-frame-unreachable.ll
@@ -0,0 +1,50 @@
+; Check that coro-split doesn't choke on intrinsics in unreachable blocks
+; RUN: opt < %s -coro-split -S
+
+define i8* @f(i1 %arg) "coroutine.presplit"="1" personality i32 0 {
+entry:
+  %arg.addr = alloca i1
+  store i1 %arg, i1* %arg.addr
+  %id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
+  %size = call i32 @llvm.coro.size.i32()
+  %alloc = call i8* @malloc(i32 %size)
+  %hdl = call i8* @llvm.coro.begin(token %id, i8* %alloc)
+  br label %cont
+
+cont:
+  %0 = call i8 @llvm.coro.suspend(token none, i1 false)
+  switch i8 %0, label %suspend [i8 0, label %resume
+                                i8 1, label %cleanup]
+resume:
+  br label %cleanup
+
+cleanup:
+  %mem = call i8* @llvm.coro.free(token %id, i8* %hdl)
+  call void @free(i8* %mem)
+  br label %suspend
+
+suspend:
+  call i1 @llvm.coro.end(i8* %hdl, i1 0)
+  ret i8* %hdl
+
+no.predecessors:
+  %argval = load i1, i1* %arg.addr
+  call void @print(i1 %argval)
+  br label %suspend
+
+}
+
+declare i8* @llvm.coro.free(token, i8*)
+declare i32 @llvm.coro.size.i32()
+declare i8  @llvm.coro.suspend(token, i1)
+declare void @llvm.coro.resume(i8*)
+declare void @llvm.coro.destroy(i8*)
+
+declare token @llvm.coro.id(i32, i8*, i8*, i8*)
+declare i1 @llvm.coro.alloc(token)
+declare i8* @llvm.coro.begin(token, i8*)
+declare i1 @llvm.coro.end(i8*, i1)
+
+declare noalias i8* @malloc(i32)
+declare void @print(i1)
+declare void @free(i8*)