Index: include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
===================================================================
--- include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
+++ include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
@@ -44,6 +44,11 @@
     /// Some kind of error has occurred and we could not legalize this
     /// instruction.
     UnableToLegalize,
+
+    /// Instruction has been replaced. To be erased after attempting
+    /// legalization on all new insts created by an inst
+    /// Mostly used by intrinsics
+    Erase,
   };
 
   LegalizerHelper(MachineFunction &MF);
Index: include/llvm/CodeGen/GlobalISel/LegalizerInfo.h
===================================================================
--- include/llvm/CodeGen/GlobalISel/LegalizerInfo.h
+++ include/llvm/CodeGen/GlobalISel/LegalizerInfo.h
@@ -16,6 +16,7 @@
 #define LLVM_CODEGEN_GLOBALISEL_MACHINELEGALIZER_H
 
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/CodeGen/GlobalISel/LegalizerHelper.h"
 #include "llvm/CodeGen/LowLevelType.h"
 #include "llvm/Target/TargetOpcodes.h"
 
@@ -192,6 +193,10 @@
                               MachineRegisterInfo &MRI,
                               MachineIRBuilder &MIRBuilder) const;
 
+  virtual LegalizerHelper::LegalizeResult
+  legalizeIntrinsic(MachineInstr &MI, MachineRegisterInfo &MRI,
+                    MachineIRBuilder &MIRBuilder) const;
+
 private:
   static const int FirstOp = TargetOpcode::PRE_ISEL_GENERIC_OPCODE_START;
   static const int LastOp = TargetOpcode::PRE_ISEL_GENERIC_OPCODE_END;
Index: lib/CodeGen/GlobalISel/Legalizer.cpp
===================================================================
--- lib/CodeGen/GlobalISel/Legalizer.cpp
+++ lib/CodeGen/GlobalISel/Legalizer.cpp
@@ -181,8 +181,11 @@
                            "unable to legalize instruction", *MI);
         return false;
       }
+      if (Res == LegalizerHelper::Erase)
+        MI->eraseFromParent();
 
-      Changed |= Res == LegalizerHelper::Legalized;
+      Changed |=
+          (Res == LegalizerHelper::Legalized || Res == LegalizerHelper::Erase);
     }
 
 
Index: lib/CodeGen/GlobalISel/LegalizerHelper.cpp
===================================================================
--- lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -35,6 +35,10 @@
 
 LegalizerHelper::LegalizeResult
 LegalizerHelper::legalizeInstrStep(MachineInstr &MI) {
+  if (TargetOpcode::G_INTRINSIC == MI.getOpcode() ||
+      TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS == MI.getOpcode())
+    return LI.legalizeIntrinsic(MI, MRI, MIRBuilder);
+
   auto Action = LI.getAction(MI, MRI);
   switch (std::get<0>(Action)) {
   case LegalizerInfo::Legal:
@@ -66,6 +70,7 @@
 
   bool Changed = false;
   LegalizeResult Res;
+  bool Erased = false;
   unsigned Idx = 0;
   do {
     Res = legalizeInstrStep(*WorkList[Idx]);
@@ -73,13 +78,14 @@
       MIRBuilder.stopRecordingInsertions();
       return UnableToLegalize;
     }
+    Erased |= Res == Erase;
     Changed |= Res == Legalized;
     ++Idx;
   } while (Idx < WorkList.size());
 
   MIRBuilder.stopRecordingInsertions();
 
-  return Changed ? Legalized : AlreadyLegal;
+  return Erased ? Erase : Changed ? Legalized : AlreadyLegal;
 }
 
 void LegalizerHelper::extractParts(unsigned Reg, LLT Ty, int NumParts,
Index: lib/CodeGen/GlobalISel/LegalizerInfo.cpp
===================================================================
--- lib/CodeGen/GlobalISel/LegalizerInfo.cpp
+++ lib/CodeGen/GlobalISel/LegalizerInfo.cpp
@@ -194,3 +194,8 @@
                                    MachineIRBuilder &MIRBuilder) const {
   return false;
 }
+LegalizerHelper::LegalizeResult
+LegalizerInfo::legalizeIntrinsic(MachineInstr &MI, MachineRegisterInfo &MRI,
+                                 MachineIRBuilder &MIRBuilder) const {
+  return LegalizerHelper::LegalizeResult::AlreadyLegal;
+}