Index: llvm/trunk/lib/Target/X86/X86InstructionSelector.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/X86InstructionSelector.cpp
+++ llvm/trunk/lib/Target/X86/X86InstructionSelector.cpp
@@ -118,6 +118,8 @@
                    MachineFunction &MF) const;
   bool selectSDiv(MachineInstr &I, MachineRegisterInfo &MRI,
                    MachineFunction &MF) const;
+  bool selectIntrinsicWSideEffects(MachineInstr &I, MachineRegisterInfo &MRI,
+                                   MachineFunction &MF) const;
 
   // emit insert subreg instruction and insert it before MachineInstr &I
   bool emitInsertSubreg(unsigned DstReg, unsigned SrcReg, MachineInstr &I,
@@ -387,6 +389,8 @@
     return selectShift(I, MRI, MF);
   case TargetOpcode::G_SDIV:
     return selectSDiv(I, MRI, MF);
+  case TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS:
+    return selectIntrinsicWSideEffects(I, MRI, MF);
   }
 
   return false;
@@ -1661,6 +1665,21 @@
   return true;
 }
 
+bool X86InstructionSelector::selectIntrinsicWSideEffects(
+    MachineInstr &I, MachineRegisterInfo &MRI, MachineFunction &MF) const {
+
+  assert(I.getOpcode() == TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS &&
+         "unexpected instruction");
+
+  if (I.getOperand(0).getIntrinsicID() != Intrinsic::trap)
+    return false;
+
+  BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(X86::TRAP));
+
+  I.eraseFromParent();
+  return true;
+}
+
 InstructionSelector *
 llvm::createX86InstructionSelector(const X86TargetMachine &TM,
                                    X86Subtarget &Subtarget,
Index: llvm/trunk/test/CodeGen/X86/GlobalISel/x86-select-trap.mir
===================================================================
--- llvm/trunk/test/CodeGen/X86/GlobalISel/x86-select-trap.mir
+++ llvm/trunk/test/CodeGen/X86/GlobalISel/x86-select-trap.mir
@@ -0,0 +1,28 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=i386-linux-gnu -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s
+
+--- |
+  declare void @llvm.trap() #0
+
+  define i32 @trap() #0 {
+    tail call void @llvm.trap()
+    unreachable
+  }
+
+  attributes #0 = { noreturn nounwind }
+  attributes #1 = { nounwind }
+
+...
+---
+name:            trap
+alignment:       4
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.1 (%ir-block.0):
+    ; CHECK-LABEL: name: trap
+    ; CHECK: TRAP
+    G_INTRINSIC_W_SIDE_EFFECTS intrinsic(@llvm.trap)
+
+...