diff --git a/include/llvm/Target/GenericOpcodes.td b/include/llvm/Target/GenericOpcodes.td
index 593cfb92cd0..e35bcb015d6 100644
--- a/include/llvm/Target/GenericOpcodes.td
+++ b/include/llvm/Target/GenericOpcodes.td
@@ -49,6 +49,12 @@ def G_TRUNC : Instruction {
   let hasSideEffects = 0;
 }
 
+def G_IMPLICIT_DEF : Instruction {
+  let OutOperandList = (outs type0:$dst);
+  let InOperandList = (ins);
+  let hasSideEffects = 0;
+}
+
 def G_FRAME_INDEX : Instruction {
   let OutOperandList = (outs type0:$dst);
   let InOperandList = (ins unknown:$src2);
diff --git a/include/llvm/Target/TargetOpcodes.def b/include/llvm/Target/TargetOpcodes.def
index 0ef39eafa66..cadf86058f0 100644
--- a/include/llvm/Target/TargetOpcodes.def
+++ b/include/llvm/Target/TargetOpcodes.def
@@ -222,6 +222,8 @@ HANDLE_TARGET_OPCODE(G_OR)
 HANDLE_TARGET_OPCODE(G_XOR)
 
 
+HANDLE_TARGET_OPCODE(G_IMPLICIT_DEF)
+
 /// Generic instruction to materialize the address of an alloca or other
 /// stack-based object.
 HANDLE_TARGET_OPCODE(G_FRAME_INDEX)
diff --git a/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 121823247e1..84b0a0ac415 100644
--- a/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -166,6 +166,20 @@ LegalizerHelper::LegalizeResult LegalizerHelper::narrowScalar(MachineInstr &MI,
   switch (MI.getOpcode()) {
   default:
     return UnableToLegalize;
+  case TargetOpcode::G_IMPLICIT_DEF: {
+    int NumParts = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits() /
+                   NarrowTy.getSizeInBits();
+
+    SmallVector<unsigned, 2> DstRegs;
+    for (int i = 0; i < NumParts; ++i) {
+      unsigned Dst = MRI.createGenericVirtualRegister(NarrowTy);
+      MIRBuilder.buildUndef(Dst);
+      DstRegs.push_back(Dst);
+    }
+    MIRBuilder.buildMerge(MI.getOperand(0).getReg(), DstRegs);
+    MI.eraseFromParent();
+    return Legalized;
+  }
   case TargetOpcode::G_ADD: {
     // Expand in terms of carry-setting/consuming G_ADDE instructions.
     int NumParts = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits() /
diff --git a/lib/CodeGen/GlobalISel/LegalizerInfo.cpp b/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
index 7e957590ede..76917aa9660 100644
--- a/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
+++ b/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
@@ -35,6 +35,8 @@
 using namespace llvm;
 
 LegalizerInfo::LegalizerInfo() {
+  DefaultActions[TargetOpcode::G_IMPLICIT_DEF] = NarrowScalar;
+
   // FIXME: these two can be legalized to the fundamental load/store Jakob
   // proposed. Once loads & stores are supported.
   DefaultActions[TargetOpcode::G_ANYEXT] = Legal;
diff --git a/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp b/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
index 3424f091ddb..47c6214c055 100644
--- a/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
+++ b/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
@@ -478,7 +478,7 @@ void MachineIRBuilder::buildSequence(unsigned Res, ArrayRef<unsigned> Ops,
 }
 
 MachineInstrBuilder MachineIRBuilder::buildUndef(unsigned Res) {
-  return buildInstr(TargetOpcode::IMPLICIT_DEF).addDef(Res);
+  return buildInstr(TargetOpcode::G_IMPLICIT_DEF).addDef(Res);
 }
 
 MachineInstrBuilder MachineIRBuilder::buildMerge(unsigned Res,
diff --git a/lib/Target/AArch64/AArch64LegalizerInfo.cpp b/lib/Target/AArch64/AArch64LegalizerInfo.cpp
index 25779774949..4b568f3fba2 100644
--- a/lib/Target/AArch64/AArch64LegalizerInfo.cpp
+++ b/lib/Target/AArch64/AArch64LegalizerInfo.cpp
@@ -39,6 +39,9 @@ AArch64LegalizerInfo::AArch64LegalizerInfo() {
   const LLT v4s32 = LLT::vector(4, 32);
   const LLT v2s64 = LLT::vector(2, 64);
 
+  for (auto Ty : {p0, s1, s8, s16, s32, s64})
+    setAction({G_IMPLICIT_DEF, Ty}, Legal);
+
   for (unsigned BinOp : {G_ADD, G_SUB, G_MUL, G_AND, G_OR, G_XOR, G_SHL}) {
     // These operations naturally get the right answer when used on
     // GPR32, even if the actual type is narrower.
diff --git a/test/CodeGen/AArch64/GlobalISel/arm64-fallback.ll b/test/CodeGen/AArch64/GlobalISel/arm64-fallback.ll
index 0298315a551..48f500eb36b 100644
--- a/test/CodeGen/AArch64/GlobalISel/arm64-fallback.ll
+++ b/test/CodeGen/AArch64/GlobalISel/arm64-fallback.ll
@@ -158,15 +158,30 @@ define fp128 @test_quad_dump() {
 ; FALLBACK-WITH-REPORT-ERR: remark: <unknown>:0:0: unable to legalize instruction: %vreg0<def>(p0) = G_EXTRACT_VECTOR_ELT %vreg1, %vreg2; (in function: vector_of_pointers_extractelement)
 ; FALLBACK-WITH-REPORT-ERR: warning: Instruction selection used fallback path for vector_of_pointers_extractelement
 ; FALLBACK-WITH-REPORT-OUT-LABEL: vector_of_pointers_extractelement:
+@var = global <2 x i16*> zeroinitializer
 define void @vector_of_pointers_extractelement() {
-  %dummy = extractelement <2 x i16*> undef, i32 0
+  br label %end
+
+block:
+  %dummy = extractelement <2 x i16*> %vec, i32 0
   ret void
+
+end:
+  %vec = load <2 x i16*>, <2 x i16*>* undef
+  br label %block
 }
 
 ; FALLBACK-WITH-REPORT-ERR: remark: <unknown>:0:0: unable to legalize instruction: %vreg0<def>(<2 x p0>) = G_INSERT_VECTOR_ELT %vreg1, %vreg2, %vreg3; (in function: vector_of_pointers_insertelement
 ; FALLBACK-WITH-REPORT-ERR: warning: Instruction selection used fallback path for vector_of_pointers_insertelement
 ; FALLBACK-WITH-REPORT-OUT-LABEL: vector_of_pointers_insertelement:
 define void @vector_of_pointers_insertelement() {
-  %dummy = insertelement <2 x i16*> undef, i16* null, i32 0
+  br label %end
+
+block:
+  %dummy = insertelement <2 x i16*> %vec, i16* null, i32 0
   ret void
+
+end:
+  %vec = load <2 x i16*>, <2 x i16*>* undef
+  br label %block
 }
diff --git a/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll b/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
index a2bcc02ca49..50ad83feed8 100644
--- a/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
+++ b/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
@@ -577,7 +577,7 @@ define i32 @constant_int_start() {
 }
 
 ; CHECK-LABEL: name: test_undef
-; CHECK: [[UNDEF:%[0-9]+]](s32) = IMPLICIT_DEF
+; CHECK: [[UNDEF:%[0-9]+]](s32) = G_IMPLICIT_DEF
 ; CHECK: %w0 = COPY [[UNDEF]]
 define i32 @test_undef() {
   ret i32 undef
@@ -807,7 +807,7 @@ define float @test_frem(float %arg1, float %arg2) {
 ; CHECK: [[RHS:%[0-9]+]](s32) = COPY %w1
 ; CHECK: [[ADDR:%[0-9]+]](p0) = COPY %x2
 ; CHECK: [[VAL:%[0-9]+]](s32), [[OVERFLOW:%[0-9]+]](s1) = G_SADDO [[LHS]], [[RHS]]
-; CHECK: [[TMP:%[0-9]+]](s64) = IMPLICIT_DEF
+; CHECK: [[TMP:%[0-9]+]](s64) = G_IMPLICIT_DEF
 ; CHECK: [[TMP1:%[0-9]+]](s64) = G_INSERT [[TMP]], [[VAL]](s32), 0
 ; CHECK: [[RES:%[0-9]+]](s64) = G_INSERT [[TMP1]], [[OVERFLOW]](s1), 32
 ; CHECK: G_STORE [[RES]](s64), [[ADDR]](p0)
@@ -824,7 +824,7 @@ define void @test_sadd_overflow(i32 %lhs, i32 %rhs, { i32, i1 }* %addr) {
 ; CHECK: [[ADDR:%[0-9]+]](p0) = COPY %x2
 ; CHECK: [[ZERO:%[0-9]+]](s1) = G_CONSTANT i1 false
 ; CHECK: [[VAL:%[0-9]+]](s32), [[OVERFLOW:%[0-9]+]](s1) = G_UADDE [[LHS]], [[RHS]], [[ZERO]]
-; CHECK: [[TMP:%[0-9]+]](s64) = IMPLICIT_DEF
+; CHECK: [[TMP:%[0-9]+]](s64) = G_IMPLICIT_DEF
 ; CHECK: [[TMP1:%[0-9]+]](s64) = G_INSERT [[TMP]], [[VAL]](s32), 0
 ; CHECK: [[RES:%[0-9]+]](s64) = G_INSERT [[TMP1]], [[OVERFLOW]](s1), 32
 ; CHECK: G_STORE [[RES]](s64), [[ADDR]](p0)
@@ -840,7 +840,7 @@ define void @test_uadd_overflow(i32 %lhs, i32 %rhs, { i32, i1 }* %addr) {
 ; CHECK: [[RHS:%[0-9]+]](s32) = COPY %w1
 ; CHECK: [[ADDR:%[0-9]+]](p0) = COPY %x2
 ; CHECK: [[VAL:%[0-9]+]](s32), [[OVERFLOW:%[0-9]+]](s1) = G_SSUBO [[LHS]], [[RHS]]
-; CHECK: [[TMP:%[0-9]+]](s64) = IMPLICIT_DEF
+; CHECK: [[TMP:%[0-9]+]](s64) = G_IMPLICIT_DEF
 ; CHECK: [[TMP1:%[0-9]+]](s64) = G_INSERT [[TMP]], [[VAL]](s32), 0
 ; CHECK: [[RES:%[0-9]+]](s64) = G_INSERT [[TMP1]], [[OVERFLOW]](s1), 32
 ; CHECK: G_STORE [[RES]](s64), [[ADDR]](p0)
@@ -857,7 +857,7 @@ define void @test_ssub_overflow(i32 %lhs, i32 %rhs, { i32, i1 }* %subr) {
 ; CHECK: [[ADDR:%[0-9]+]](p0) = COPY %x2
 ; CHECK: [[ZERO:%[0-9]+]](s1) = G_CONSTANT i1 false
 ; CHECK: [[VAL:%[0-9]+]](s32), [[OVERFLOW:%[0-9]+]](s1) = G_USUBE [[LHS]], [[RHS]], [[ZERO]]
-; CHECK: [[TMP:%[0-9]+]](s64) = IMPLICIT_DEF
+; CHECK: [[TMP:%[0-9]+]](s64) = G_IMPLICIT_DEF
 ; CHECK: [[TMP1:%[0-9]+]](s64) = G_INSERT [[TMP]], [[VAL]](s32), 0
 ; CHECK: [[RES:%[0-9]+]](s64) = G_INSERT [[TMP1]], [[OVERFLOW]](s1), 32
 ; CHECK: G_STORE [[RES]](s64), [[ADDR]](p0)
@@ -873,7 +873,7 @@ define void @test_usub_overflow(i32 %lhs, i32 %rhs, { i32, i1 }* %subr) {
 ; CHECK: [[RHS:%[0-9]+]](s32) = COPY %w1
 ; CHECK: [[ADDR:%[0-9]+]](p0) = COPY %x2
 ; CHECK: [[VAL:%[0-9]+]](s32), [[OVERFLOW:%[0-9]+]](s1) = G_SMULO [[LHS]], [[RHS]]
-; CHECK: [[TMP:%[0-9]+]](s64) = IMPLICIT_DEF
+; CHECK: [[TMP:%[0-9]+]](s64) = G_IMPLICIT_DEF
 ; CHECK: [[TMP1:%[0-9]+]](s64) = G_INSERT [[TMP]], [[VAL]](s32), 0
 ; CHECK: [[RES:%[0-9]+]](s64) = G_INSERT [[TMP1]], [[OVERFLOW]](s1), 32
 ; CHECK: G_STORE [[RES]](s64), [[ADDR]](p0)
@@ -889,7 +889,7 @@ define void @test_smul_overflow(i32 %lhs, i32 %rhs, { i32, i1 }* %addr) {
 ; CHECK: [[RHS:%[0-9]+]](s32) = COPY %w1
 ; CHECK: [[ADDR:%[0-9]+]](p0) = COPY %x2
 ; CHECK: [[VAL:%[0-9]+]](s32), [[OVERFLOW:%[0-9]+]](s1) = G_UMULO [[LHS]], [[RHS]]
-; CHECK: [[TMP:%[0-9]+]](s64) = IMPLICIT_DEF
+; CHECK: [[TMP:%[0-9]+]](s64) = G_IMPLICIT_DEF
 ; CHECK: [[TMP1:%[0-9]+]](s64) = G_INSERT [[TMP]], [[VAL]](s32), 0
 ; CHECK: [[RES:%[0-9]+]](s64) = G_INSERT [[TMP1]], [[OVERFLOW]](s1), 32
 ; CHECK: G_STORE [[RES]](s64), [[ADDR]](p0)
@@ -1503,7 +1503,7 @@ define float @test_different_call_conv_target(float %x) {
 define <2 x i32> @test_shufflevector_s32_v2s32(i32 %arg) {
 ; CHECK-LABEL: name: test_shufflevector_s32_v2s32
 ; CHECK: [[ARG:%[0-9]+]](s32) = COPY %w0
-; CHECK-DAG: [[UNDEF:%[0-9]+]](s32) = IMPLICIT_DEF
+; CHECK-DAG: [[UNDEF:%[0-9]+]](s32) = G_IMPLICIT_DEF
 ; CHECK-DAG: [[C0:%[0-9]+]](s32) = G_CONSTANT i32 0
 ; CHECK-DAG: [[MASK:%[0-9]+]](<2 x s32>) = G_MERGE_VALUES [[C0]](s32), [[C0]](s32)
 ; CHECK: [[VEC:%[0-9]+]](<2 x s32>) = G_SHUFFLE_VECTOR [[ARG]](s32), [[UNDEF]], [[MASK]](<2 x s32>)
@@ -1516,7 +1516,7 @@ define <2 x i32> @test_shufflevector_s32_v2s32(i32 %arg) {
 define i32 @test_shufflevector_v2s32_s32(<2 x i32> %arg) {
 ; CHECK-LABEL: name: test_shufflevector_v2s32_s32
 ; CHECK: [[ARG:%[0-9]+]](<2 x s32>) = COPY %d0
-; CHECK-DAG: [[UNDEF:%[0-9]+]](<2 x s32>) = IMPLICIT_DEF
+; CHECK-DAG: [[UNDEF:%[0-9]+]](<2 x s32>) = G_IMPLICIT_DEF
 ; CHECK-DAG: [[C1:%[0-9]+]](s32) = G_CONSTANT i32 1
 ; CHECK: [[RES:%[0-9]+]](s32) = G_SHUFFLE_VECTOR [[ARG]](<2 x s32>), [[UNDEF]], [[C1]](s32)
 ; CHECK: %w0 = COPY [[RES]](s32)
@@ -1528,7 +1528,7 @@ define i32 @test_shufflevector_v2s32_s32(<2 x i32> %arg) {
 define <2 x i32> @test_shufflevector_v2s32_v2s32(<2 x i32> %arg) {
 ; CHECK-LABEL: name: test_shufflevector_v2s32_v2s32
 ; CHECK: [[ARG:%[0-9]+]](<2 x s32>) = COPY %d0
-; CHECK-DAG: [[UNDEF:%[0-9]+]](<2 x s32>) = IMPLICIT_DEF
+; CHECK-DAG: [[UNDEF:%[0-9]+]](<2 x s32>) = G_IMPLICIT_DEF
 ; CHECK-DAG: [[C1:%[0-9]+]](s32) = G_CONSTANT i32 1
 ; CHECK-DAG: [[C0:%[0-9]+]](s32) = G_CONSTANT i32 0
 ; CHECK-DAG: [[MASK:%[0-9]+]](<2 x s32>) = G_MERGE_VALUES [[C1]](s32), [[C0]](s32)
@@ -1541,7 +1541,7 @@ define <2 x i32> @test_shufflevector_v2s32_v2s32(<2 x i32> %arg) {
 define i32 @test_shufflevector_v2s32_v3s32(<2 x i32> %arg) {
 ; CHECK-LABEL: name: test_shufflevector_v2s32_v3s32
 ; CHECK: [[ARG:%[0-9]+]](<2 x s32>) = COPY %d0
-; CHECK-DAG: [[UNDEF:%[0-9]+]](<2 x s32>) = IMPLICIT_DEF
+; CHECK-DAG: [[UNDEF:%[0-9]+]](<2 x s32>) = G_IMPLICIT_DEF
 ; CHECK-DAG: [[C1:%[0-9]+]](s32) = G_CONSTANT i32 1
 ; CHECK-DAG: [[C0:%[0-9]+]](s32) = G_CONSTANT i32 0
 ; CHECK-DAG: [[MASK:%[0-9]+]](<3 x s32>) = G_MERGE_VALUES [[C1]](s32), [[C0]](s32), [[C1]](s32)
@@ -1570,7 +1570,7 @@ define <4 x i32> @test_shufflevector_v2s32_v4s32(<2 x i32> %arg1, <2 x i32> %arg
 define <2 x i32> @test_shufflevector_v4s32_v2s32(<4 x i32> %arg) {
 ; CHECK-LABEL: name: test_shufflevector_v4s32_v2s32
 ; CHECK: [[ARG:%[0-9]+]](<4 x s32>) = COPY %q0
-; CHECK-DAG: [[UNDEF:%[0-9]+]](<4 x s32>) = IMPLICIT_DEF
+; CHECK-DAG: [[UNDEF:%[0-9]+]](<4 x s32>) = G_IMPLICIT_DEF
 ; CHECK-DAG: [[C1:%[0-9]+]](s32) = G_CONSTANT i32 1
 ; CHECK-DAG: [[C3:%[0-9]+]](s32) = G_CONSTANT i32 3
 ; CHECK-DAG: [[MASK:%[0-9]+]](<2 x s32>) = G_MERGE_VALUES [[C1]](s32), [[C3]](s32)
@@ -1609,7 +1609,7 @@ define <16 x i8> @test_shufflevector_v8s8_v16s8(<8 x i8> %arg1, <8 x i8> %arg2)
 }
 
 ; CHECK-LABEL: test_constant_vector
-; CHECK: [[UNDEF:%[0-9]+]](s16) = IMPLICIT_DEF
+; CHECK: [[UNDEF:%[0-9]+]](s16) = G_IMPLICIT_DEF
 ; CHECK: [[F:%[0-9]+]](s16) = G_FCONSTANT half 0xH3C00
 ; CHECK: [[M:%[0-9]+]](<4 x s16>) = G_MERGE_VALUES [[UNDEF]](s16), [[UNDEF]](s16), [[UNDEF]](s16), [[F]](s16)
 ; CHECK: %d0 = COPY [[M]](<4 x s16>)
diff --git a/test/CodeGen/AArch64/GlobalISel/call-translator.ll b/test/CodeGen/AArch64/GlobalISel/call-translator.ll
index 0e593fdb7b8..8fba8e09f9f 100644
--- a/test/CodeGen/AArch64/GlobalISel/call-translator.ll
+++ b/test/CodeGen/AArch64/GlobalISel/call-translator.ll
@@ -64,7 +64,7 @@ define void @test_multiple_args(i64 %in) {
 ; CHECK: [[I8:%[0-9]+]](s8) = COPY %w1
 ; CHECK: [[ADDR:%[0-9]+]](p0) = COPY %x2
 
-; CHECK: [[UNDEF:%[0-9]+]](s192) = IMPLICIT_DEF
+; CHECK: [[UNDEF:%[0-9]+]](s192) = G_IMPLICIT_DEF
 ; CHECK: [[ARG0:%[0-9]+]](s192) = G_INSERT [[UNDEF]], [[DBL]](s64), 0
 ; CHECK: [[ARG1:%[0-9]+]](s192) = G_INSERT [[ARG0]], [[I64]](s64), 64
 ; CHECK: [[ARG2:%[0-9]+]](s192) = G_INSERT [[ARG1]], [[I8]](s8), 128
diff --git a/test/CodeGen/AArch64/GlobalISel/irtranslator-exceptions.ll b/test/CodeGen/AArch64/GlobalISel/irtranslator-exceptions.ll
index ef4445111d7..d9fec0ec7d4 100644
--- a/test/CodeGen/AArch64/GlobalISel/irtranslator-exceptions.ll
+++ b/test/CodeGen/AArch64/GlobalISel/irtranslator-exceptions.ll
@@ -19,7 +19,7 @@ declare i32 @llvm.eh.typeid.for(i8*)
 
 ; CHECK:   [[BAD]] (landing-pad):
 ; CHECK:     EH_LABEL
-; CHECK:     [[UNDEF:%[0-9]+]](s128) = IMPLICIT_DEF
+; CHECK:     [[UNDEF:%[0-9]+]](s128) = G_IMPLICIT_DEF
 ; CHECK:     [[PTR:%[0-9]+]](p0) = COPY %x0
 ; CHECK:     [[VAL_WITH_PTR:%[0-9]+]](s128) = G_INSERT [[UNDEF]], [[PTR]](p0), 0
 ; CHECK:     [[SEL_PTR:%[0-9]+]](p0) = COPY %x1
diff --git a/test/CodeGen/AArch64/GlobalISel/legalize-undef.mir b/test/CodeGen/AArch64/GlobalISel/legalize-undef.mir
new file mode 100644
index 00000000000..e7cf59b3394
--- /dev/null
+++ b/test/CodeGen/AArch64/GlobalISel/legalize-undef.mir
@@ -0,0 +1,15 @@
+# RUN: llc -mtriple=aarch64-linux-gnu -O0 -run-pass=legalizer -global-isel %s -o - | FileCheck %s
+
+---
+name:            test_implicit_def
+registers:
+body: |
+  bb.0.entry:
+    liveins:
+    ; CHECK-LABEL: name: test_implicit_def
+    ; CHECK: [[LO:%[0-9]+]](s64) = G_IMPLICIT_DEF
+    ; CHECK: [[HI:%[0-9]+]](s64) = G_IMPLICIT_DEF
+    ; CHECK: %0(s128) = G_MERGE_VALUES [[LO]](s64), [[HI]](s64)
+
+    %0:_(s128) = G_IMPLICIT_DEF
+...
diff --git a/test/CodeGen/ARM/GlobalISel/arm-irtranslator.ll b/test/CodeGen/ARM/GlobalISel/arm-irtranslator.ll
index 0ff8d52e94c..f50916e4b47 100644
--- a/test/CodeGen/ARM/GlobalISel/arm-irtranslator.ll
+++ b/test/CodeGen/ARM/GlobalISel/arm-irtranslator.ll
@@ -910,7 +910,7 @@ define arm_aapcscc {i32, i32} @test_structs({i32, i32} %x) {
 define i32 @test_shufflevector_s32_v2s32(i32 %arg) {
 ; CHECK-LABEL: name: test_shufflevector_s32_v2s32
 ; CHECK: [[ARG:%[0-9]+]](s32) = COPY %r0
-; CHECK-DAG: [[UNDEF:%[0-9]+]](s32) = IMPLICIT_DEF
+; CHECK-DAG: [[UNDEF:%[0-9]+]](s32) = G_IMPLICIT_DEF
 ; CHECK-DAG: [[C0:%[0-9]+]](s32) = G_CONSTANT i32 0
 ; CHECK-DAG: [[MASK:%[0-9]+]](<2 x s32>) = G_MERGE_VALUES [[C0]](s32), [[C0]](s32)
 ; CHECK: [[VEC:%[0-9]+]](<2 x s32>) = G_SHUFFLE_VECTOR [[ARG]](s32), [[UNDEF]], [[MASK]](<2 x s32>)
@@ -925,7 +925,7 @@ define i32 @test_shufflevector_v2s32_v3s32(i32 %arg1, i32 %arg2) {
 ; CHECK-LABEL: name: test_shufflevector_v2s32_v3s32
 ; CHECK: [[ARG1:%[0-9]+]](s32) = COPY %r0
 ; CHECK: [[ARG2:%[0-9]+]](s32) = COPY %r1
-; CHECK-DAG: [[UNDEF:%[0-9]+]](<2 x s32>) = IMPLICIT_DEF
+; CHECK-DAG: [[UNDEF:%[0-9]+]](<2 x s32>) = G_IMPLICIT_DEF
 ; CHECK-DAG: [[C0:%[0-9]+]](s32) = G_CONSTANT i32 0
 ; CHECK-DAG: [[C1:%[0-9]+]](s32) = G_CONSTANT i32 1
 ; CHECK-DAG: [[MASK:%[0-9]+]](<3 x s32>) = G_MERGE_VALUES [[C1]](s32), [[C0]](s32), [[C1]](s32)
@@ -945,7 +945,7 @@ define i32 @test_shufflevector_v2s32_v4s32(i32 %arg1, i32 %arg2) {
 ; CHECK-LABEL: name: test_shufflevector_v2s32_v4s32
 ; CHECK: [[ARG1:%[0-9]+]](s32) = COPY %r0
 ; CHECK: [[ARG2:%[0-9]+]](s32) = COPY %r1
-; CHECK-DAG: [[UNDEF:%[0-9]+]](<2 x s32>) = IMPLICIT_DEF
+; CHECK-DAG: [[UNDEF:%[0-9]+]](<2 x s32>) = G_IMPLICIT_DEF
 ; CHECK-DAG: [[C0:%[0-9]+]](s32) = G_CONSTANT i32 0
 ; CHECK-DAG: [[C1:%[0-9]+]](s32) = G_CONSTANT i32 1
 ; CHECK-DAG: [[MASK:%[0-9]+]](<4 x s32>) = G_MERGE_VALUES [[C0]](s32), [[C0]](s32), [[C0]](s32), [[C0]](s32)
@@ -966,7 +966,7 @@ define i32 @test_shufflevector_v4s32_v2s32(i32 %arg1, i32 %arg2, i32 %arg3, i32
 ; CHECK: [[ARG2:%[0-9]+]](s32) = COPY %r1
 ; CHECK: [[ARG3:%[0-9]+]](s32) = COPY %r2
 ; CHECK: [[ARG4:%[0-9]+]](s32) = COPY %r3
-; CHECK-DAG: [[UNDEF:%[0-9]+]](<4 x s32>) = IMPLICIT_DEF
+; CHECK-DAG: [[UNDEF:%[0-9]+]](<4 x s32>) = G_IMPLICIT_DEF
 ; CHECK-DAG: [[C0:%[0-9]+]](s32) = G_CONSTANT i32 0
 ; CHECK-DAG: [[C1:%[0-9]+]](s32) = G_CONSTANT i32 1
 ; CHECK-DAG: [[C2:%[0-9]+]](s32) = G_CONSTANT i32 2
@@ -1009,7 +1009,7 @@ define i32 @test_constantstruct_v2s32_s32_s32() {
 ; CHECK: [[VEC:%[0-9]+]](<2 x s32>) = G_MERGE_VALUES [[C1]](s32), [[C2]](s32)
 ; CHECK: [[C3:%[0-9]+]](s32) = G_CONSTANT i32 3
 ; CHECK: [[C4:%[0-9]+]](s32) = G_CONSTANT i32 4
-; CHECK: [[C5:%[0-9]+]](s128) = IMPLICIT_DEF
+; CHECK: [[C5:%[0-9]+]](s128) = G_IMPLICIT_DEF
 ; CHECK: [[C6:%[0-9]+]](s128) = G_INSERT [[C5]], [[VEC]](<2 x s32>), 0
 ; CHECK: [[C7:%[0-9]+]](s128) = G_INSERT [[C6]], [[C3]](s32), 64
 ; CHECK: [[C8:%[0-9]+]](s128) = G_INSERT [[C7]], [[C4]](s32), 96