1 files changed, 14 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp b/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
index bda7a46..9f3f2d6 100644
--- a/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
+++ b/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
@@ -26,6 +26,7 @@
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/MDBuilder.h"
 #include "llvm/IR/PassManager.h"
 #include "llvm/InitializePasses.h"
@@ -769,9 +770,21 @@ CHRScope * CHR::findScope(Region *R) {
       return nullptr;
   // If any of the basic blocks have address taken, we must skip this region
   // because we cannot clone basic blocks that have address taken.
-  for (BasicBlock *BB : R->blocks())
+  for (BasicBlock *BB : R->blocks()) {
     if (BB->hasAddressTaken())
       return nullptr;
+    // If we encounter llvm.coro.id, skip this region because if the basic block
+    // is cloned, we end up inserting a token type PHI node to the block with
+    // llvm.coro.begin.
+    // FIXME: This could lead to less optimal codegen, because the region is
+    // excluded, it can prevent CHR from merging adjacent regions into bigger
+    // scope and hoisting more branches.
+    for (Instruction &I : *BB)
+      if (auto *II = dyn_cast<IntrinsicInst>(&I))
+        if (II->getIntrinsicID() == Intrinsic::coro_id)
+          return nullptr;
+  }
+
   if (Exit) {
     // Try to find an if-then block (check if R is an if-then).
     // if (cond) {