Mark setjmp as "returns twice" and turn off SimpleCoalescing when called.

src/IceTargetLowering.cpp

Index: src/IceTargetLowering.cpp
diff --git a/src/IceTargetLowering.cpp b/src/IceTargetLowering.cpp
index 71788dfc8dd011b03b5ab8f1bccdea0ff181370f..4ab6c63dc577e23fca7eb2933c97f4eee84fb62b 100644
--- a/src/IceTargetLowering.cpp
+++ b/src/IceTargetLowering.cpp
@@ -171,9 +171,13 @@ void TargetLowering::lower() {
   case Inst::InsertElement:
     lowerInsertElement(llvm::dyn_cast<InstInsertElement>(Inst));
     break;
-  case Inst::IntrinsicCall:
-    lowerIntrinsicCall(llvm::dyn_cast<InstIntrinsicCall>(Inst));
+  case Inst::IntrinsicCall: {
+    InstIntrinsicCall *Call = llvm::dyn_cast<InstIntrinsicCall>(Inst);
+    if (Call->getIntrinsicInfo().ReturnsTwice)
+      setCallsReturnsTwice(true);
+    lowerIntrinsicCall(Call);
     break;
+  }
   case Inst::Load:
     lowerLoad(llvm::dyn_cast<InstLoad>(Inst));
     break;