Index: include/llvm/CodeGen/GlobalISel/LegalizationArtifactCombiner.h
===================================================================
--- include/llvm/CodeGen/GlobalISel/LegalizationArtifactCombiner.h
+++ include/llvm/CodeGen/GlobalISel/LegalizationArtifactCombiner.h
@@ -203,14 +203,33 @@
     return false;
   }
 
-  static unsigned getMergeOpcode(LLT OpTy, LLT DestTy) {
+  static unsigned canFoldMergeOpcode(unsigned MergeOp, unsigned ConvertOp,
+                                     LLT OpTy, LLT DestTy) {
     if (OpTy.isVector() && DestTy.isVector())
-      return TargetOpcode::G_CONCAT_VECTORS;
+      return MergeOp == TargetOpcode::G_CONCAT_VECTORS;
 
-    if (OpTy.isVector() && !DestTy.isVector())
-      return TargetOpcode::G_BUILD_VECTOR;
+    if (OpTy.isVector() && !DestTy.isVector()) {
+      if (MergeOp == TargetOpcode::G_BUILD_VECTOR)
+        return true;
+
+      if (MergeOp == TargetOpcode::G_CONCAT_VECTORS) {
+        if (ConvertOp == 0)
+          return true;
+
+        const unsigned OpEltSize = OpTy.getElementType().getSizeInBits();
+
+        // Don't handle scalarization with a cast that isn't in the same
+        // direction as the vector cast. This could be handled, but it would
+        // require more intermediate unmerges.
+        if (ConvertOp == TargetOpcode::G_TRUNC)
+          return DestTy.getSizeInBits() <= OpEltSize;
+        return DestTy.getSizeInBits() >= OpEltSize;
+      }
 
-    return TargetOpcode::G_MERGE_VALUES;
+      return false;
+    }
+
+    return MergeOp == TargetOpcode::G_MERGE_VALUES;
   }
 
   bool tryCombineMerges(MachineInstr &MI,
@@ -237,16 +256,14 @@
       MergeI = getDefIgnoringCopies(SrcDef->getOperand(1).getReg(), MRI);
     }
 
-    // FIXME: Handle scalarizing concat_vectors (scalar result type with vector
-    // source)
-    unsigned MergingOpcode = getMergeOpcode(OpTy, DestTy);
-    if (!MergeI || MergeI->getOpcode() != MergingOpcode)
+    if (!MergeI || !canFoldMergeOpcode(MergeI->getOpcode(),
+                                       ConvertOp, OpTy, DestTy))
       return false;
 
     const unsigned NumMergeRegs = MergeI->getNumOperands() - 1;
 
     if (NumMergeRegs < NumDefs) {
-      if (ConvertOp != 0 || NumDefs % NumMergeRegs != 0)
+      if (NumDefs % NumMergeRegs != 0)
         return false;
 
       Builder.setInstr(MI);
@@ -264,7 +281,22 @@
              ++j, ++DefIdx)
           DstRegs.push_back(MI.getOperand(DefIdx).getReg());
 
-        Builder.buildUnmerge(DstRegs, MergeI->getOperand(Idx + 1).getReg());
+        if (ConvertOp) {
+          SmallVector<Register, 2> TmpRegs;
+          // This is a vector that is being scalarized and casted. Extract to
+          // the element type, and do the conversion on the scalars.
+          LLT MergeEltTy
+            = MRI.getType(MergeI->getOperand(0).getReg()).getElementType();
+          for (unsigned j = 0; j < NumMergeRegs; ++j)
+            TmpRegs.push_back(MRI.createGenericVirtualRegister(MergeEltTy));
+
+          Builder.buildUnmerge(TmpRegs, MergeI->getOperand(Idx + 1).getReg());
+
+          for (unsigned j = 0; j < NumMergeRegs; ++j)
+            Builder.buildInstr(ConvertOp, {DstRegs[j]}, {TmpRegs[j]});
+        } else {
+          Builder.buildUnmerge(DstRegs, MergeI->getOperand(Idx + 1).getReg());
+        }
       }
 
     } else if (NumMergeRegs > NumDefs) {
Index: test/CodeGen/AMDGPU/GlobalISel/artifact-combiner-unmerge-values.mir
===================================================================
--- test/CodeGen/AMDGPU/GlobalISel/artifact-combiner-unmerge-values.mir
+++ test/CodeGen/AMDGPU/GlobalISel/artifact-combiner-unmerge-values.mir
@@ -225,17 +225,25 @@
     ; CHECK-LABEL: name: test_unmerge_values_s1_trunc_v4s1_of_concat_vectors_v4s32_v2s32
     ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr0_vgpr1
     ; CHECK: [[COPY1:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr2_vgpr3
-    ; CHECK: [[CONCAT_VECTORS:%[0-9]+]]:_(<4 x s32>) = G_CONCAT_VECTORS [[COPY]](<2 x s32>), [[COPY1]](<2 x s32>)
-    ; CHECK: [[TRUNC:%[0-9]+]]:_(<4 x s1>) = G_TRUNC [[CONCAT_VECTORS]](<4 x s32>)
-    ; CHECK: [[UV:%[0-9]+]]:_(s1), [[UV1:%[0-9]+]]:_(s1), [[UV2:%[0-9]+]]:_(s1), [[UV3:%[0-9]+]]:_(s1) = G_UNMERGE_VALUES [[TRUNC]](<4 x s1>)
-    ; CHECK: [[SEXT:%[0-9]+]]:_(s32) = G_SEXT [[UV]](s1)
-    ; CHECK: [[SEXT1:%[0-9]+]]:_(s32) = G_SEXT [[UV1]](s1)
-    ; CHECK: [[SEXT2:%[0-9]+]]:_(s32) = G_SEXT [[UV2]](s1)
-    ; CHECK: [[SEXT3:%[0-9]+]]:_(s32) = G_SEXT [[UV3]](s1)
-    ; CHECK: $vgpr0 = COPY [[SEXT]](s32)
-    ; CHECK: $vgpr1 = COPY [[SEXT1]](s32)
-    ; CHECK: $vgpr2 = COPY [[SEXT2]](s32)
-    ; CHECK: $vgpr3 = COPY [[SEXT3]](s32)
+    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY]](<2 x s32>)
+    ; CHECK: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY1]](<2 x s32>)
+    ; CHECK: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 31
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY [[UV]](s32)
+    ; CHECK: [[SHL:%[0-9]+]]:_(s32) = G_SHL [[COPY2]], [[C]](s32)
+    ; CHECK: [[ASHR:%[0-9]+]]:_(s32) = G_ASHR [[SHL]], [[C]](s32)
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY [[UV1]](s32)
+    ; CHECK: [[SHL1:%[0-9]+]]:_(s32) = G_SHL [[COPY3]], [[C]](s32)
+    ; CHECK: [[ASHR1:%[0-9]+]]:_(s32) = G_ASHR [[SHL1]], [[C]](s32)
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s32) = COPY [[UV2]](s32)
+    ; CHECK: [[SHL2:%[0-9]+]]:_(s32) = G_SHL [[COPY4]], [[C]](s32)
+    ; CHECK: [[ASHR2:%[0-9]+]]:_(s32) = G_ASHR [[SHL2]], [[C]](s32)
+    ; CHECK: [[COPY5:%[0-9]+]]:_(s32) = COPY [[UV3]](s32)
+    ; CHECK: [[SHL3:%[0-9]+]]:_(s32) = G_SHL [[COPY5]], [[C]](s32)
+    ; CHECK: [[ASHR3:%[0-9]+]]:_(s32) = G_ASHR [[SHL3]], [[C]](s32)
+    ; CHECK: $vgpr0 = COPY [[ASHR]](s32)
+    ; CHECK: $vgpr1 = COPY [[ASHR1]](s32)
+    ; CHECK: $vgpr2 = COPY [[ASHR2]](s32)
+    ; CHECK: $vgpr3 = COPY [[ASHR3]](s32)
     %0:_(<2 x s32>) = COPY $vgpr0_vgpr1
     %1:_(<2 x s32>) = COPY $vgpr2_vgpr3
     %2:_(<4 x s32>) = G_CONCAT_VECTORS %0, %1
@@ -258,8 +266,8 @@
     ; CHECK-LABEL: name: test_unmerge_values_s16_of_concat_vectors_v2s16_v2s16
     ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s16>) = COPY $vgpr0
     ; CHECK: [[COPY1:%[0-9]+]]:_(<2 x s16>) = COPY $vgpr1
-    ; CHECK: [[CONCAT_VECTORS:%[0-9]+]]:_(<4 x s16>) = G_CONCAT_VECTORS [[COPY]](<2 x s16>), [[COPY1]](<2 x s16>)
-    ; CHECK: [[UV:%[0-9]+]]:_(s16), [[UV1:%[0-9]+]]:_(s16), [[UV2:%[0-9]+]]:_(s16), [[UV3:%[0-9]+]]:_(s16) = G_UNMERGE_VALUES [[CONCAT_VECTORS]](<4 x s16>)
+    ; CHECK: [[UV:%[0-9]+]]:_(s16), [[UV1:%[0-9]+]]:_(s16) = G_UNMERGE_VALUES [[COPY]](<2 x s16>)
+    ; CHECK: [[UV2:%[0-9]+]]:_(s16), [[UV3:%[0-9]+]]:_(s16) = G_UNMERGE_VALUES [[COPY1]](<2 x s16>)
     ; CHECK: S_ENDPGM 0, implicit [[UV]](s16), implicit [[UV1]](s16), implicit [[UV2]](s16), implicit [[UV3]](s16)
     %0:_(<2 x s16>) = COPY $vgpr0
     %1:_(<2 x s16>) = COPY $vgpr1
@@ -275,8 +283,8 @@
     ; CHECK-LABEL: name: test_unmerge_values_s32_of_concat_vectors_v2s32_v2s32
     ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr0_vgpr1
     ; CHECK: [[COPY1:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr1_vgpr2
-    ; CHECK: [[CONCAT_VECTORS:%[0-9]+]]:_(<4 x s32>) = G_CONCAT_VECTORS [[COPY]](<2 x s32>), [[COPY1]](<2 x s32>)
-    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32), [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CONCAT_VECTORS]](<4 x s32>)
+    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY]](<2 x s32>)
+    ; CHECK: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY1]](<2 x s32>)
     ; CHECK: S_ENDPGM 0, implicit [[UV]](s32), implicit [[UV1]](s32), implicit [[UV2]](s32), implicit [[UV3]](s32)
     %0:_(<2 x s32>) = COPY $vgpr0_vgpr1
     %1:_(<2 x s32>) = COPY $vgpr1_vgpr2
@@ -292,8 +300,8 @@
     ; CHECK-LABEL: name: test_unmerge_values_s32_of_concat_vectors_v2s64_v2s64
     ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s64>) = COPY $vgpr0_vgpr1_vgpr2_vgpr3
     ; CHECK: [[COPY1:%[0-9]+]]:_(<2 x s64>) = COPY $vgpr4_vgpr5_vgpr6_vgpr7
-    ; CHECK: [[CONCAT_VECTORS:%[0-9]+]]:_(<4 x s64>) = G_CONCAT_VECTORS [[COPY]](<2 x s64>), [[COPY1]](<2 x s64>)
-    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32), [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32), [[UV4:%[0-9]+]]:_(s32), [[UV5:%[0-9]+]]:_(s32), [[UV6:%[0-9]+]]:_(s32), [[UV7:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CONCAT_VECTORS]](<4 x s64>)
+    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32), [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY]](<2 x s64>)
+    ; CHECK: [[UV4:%[0-9]+]]:_(s32), [[UV5:%[0-9]+]]:_(s32), [[UV6:%[0-9]+]]:_(s32), [[UV7:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY1]](<2 x s64>)
     ; CHECK: S_ENDPGM 0, implicit [[UV]](s32), implicit [[UV1]](s32), implicit [[UV2]](s32), implicit [[UV3]](s32), implicit [[UV4]](s32), implicit [[UV5]](s32), implicit [[UV6]](s32), implicit [[UV7]](s32)
     %0:_(<2 x s64>) = COPY $vgpr0_vgpr1_vgpr2_vgpr3
     %1:_(<2 x s64>) = COPY $vgpr4_vgpr5_vgpr6_vgpr7
@@ -309,10 +317,13 @@
     ; CHECK-LABEL: name: test_unmerge_values_s32_of_trunc_concat_vectors_v2s64_v2s64
     ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s64>) = COPY $vgpr0_vgpr1_vgpr2_vgpr3
     ; CHECK: [[COPY1:%[0-9]+]]:_(<2 x s64>) = COPY $vgpr4_vgpr5_vgpr6_vgpr7
-    ; CHECK: [[CONCAT_VECTORS:%[0-9]+]]:_(<4 x s64>) = G_CONCAT_VECTORS [[COPY]](<2 x s64>), [[COPY1]](<2 x s64>)
-    ; CHECK: [[TRUNC:%[0-9]+]]:_(<4 x s32>) = G_TRUNC [[CONCAT_VECTORS]](<4 x s64>)
-    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32), [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[TRUNC]](<4 x s32>)
-    ; CHECK: S_ENDPGM 0, implicit [[UV]](s32), implicit [[UV1]](s32), implicit [[UV2]](s32), implicit [[UV3]](s32)
+    ; CHECK: [[UV:%[0-9]+]]:_(s64), [[UV1:%[0-9]+]]:_(s64) = G_UNMERGE_VALUES [[COPY]](<2 x s64>)
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s32) = G_TRUNC [[UV]](s64)
+    ; CHECK: [[TRUNC1:%[0-9]+]]:_(s32) = G_TRUNC [[UV1]](s64)
+    ; CHECK: [[UV2:%[0-9]+]]:_(s64), [[UV3:%[0-9]+]]:_(s64) = G_UNMERGE_VALUES [[COPY1]](<2 x s64>)
+    ; CHECK: [[TRUNC2:%[0-9]+]]:_(s32) = G_TRUNC [[UV2]](s64)
+    ; CHECK: [[TRUNC3:%[0-9]+]]:_(s32) = G_TRUNC [[UV3]](s64)
+    ; CHECK: S_ENDPGM 0, implicit [[TRUNC]](s32), implicit [[TRUNC1]](s32), implicit [[TRUNC2]](s32), implicit [[TRUNC3]](s32)
     %0:_(<2 x s64>) = COPY $vgpr0_vgpr1_vgpr2_vgpr3
     %1:_(<2 x s64>) = COPY $vgpr4_vgpr5_vgpr6_vgpr7
     %2:_(<4 x s64>) = G_CONCAT_VECTORS %0, %1
@@ -328,15 +339,13 @@
     ; CHECK-LABEL: name: test_unmerge_values_s64_of_sext_concat_vectors_v2s32_v2s32
     ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr0_vgpr1
     ; CHECK: [[COPY1:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr2_vgpr3
-    ; CHECK: [[CONCAT_VECTORS:%[0-9]+]]:_(<4 x s32>) = G_CONCAT_VECTORS [[COPY]](<2 x s32>), [[COPY1]](<2 x s32>)
-    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32), [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CONCAT_VECTORS]](<4 x s32>)
+    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY]](<2 x s32>)
     ; CHECK: [[SEXT:%[0-9]+]]:_(s64) = G_SEXT [[UV]](s32)
     ; CHECK: [[SEXT1:%[0-9]+]]:_(s64) = G_SEXT [[UV1]](s32)
+    ; CHECK: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY1]](<2 x s32>)
     ; CHECK: [[SEXT2:%[0-9]+]]:_(s64) = G_SEXT [[UV2]](s32)
     ; CHECK: [[SEXT3:%[0-9]+]]:_(s64) = G_SEXT [[UV3]](s32)
-    ; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<4 x s64>) = G_BUILD_VECTOR [[SEXT]](s64), [[SEXT1]](s64), [[SEXT2]](s64), [[SEXT3]](s64)
-    ; CHECK: [[UV4:%[0-9]+]]:_(s64), [[UV5:%[0-9]+]]:_(s64), [[UV6:%[0-9]+]]:_(s64), [[UV7:%[0-9]+]]:_(s64) = G_UNMERGE_VALUES [[BUILD_VECTOR]](<4 x s64>)
-    ; CHECK: S_ENDPGM 0, implicit [[UV4]](s64), implicit [[UV5]](s64), implicit [[UV6]](s64), implicit [[UV7]](s64)
+    ; CHECK: S_ENDPGM 0, implicit [[SEXT]](s64), implicit [[SEXT1]](s64), implicit [[SEXT2]](s64), implicit [[SEXT3]](s64)
     %0:_(<2 x s32>) = COPY $vgpr0_vgpr1
     %1:_(<2 x s32>) = COPY $vgpr2_vgpr3
     %2:_(<4 x s32>) = G_CONCAT_VECTORS %0, %1
@@ -352,15 +361,13 @@
     ; CHECK-LABEL: name: test_unmerge_values_s64_of_zext_concat_vectors_v2s32_v2s32
     ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr0_vgpr1
     ; CHECK: [[COPY1:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr2_vgpr3
-    ; CHECK: [[CONCAT_VECTORS:%[0-9]+]]:_(<4 x s32>) = G_CONCAT_VECTORS [[COPY]](<2 x s32>), [[COPY1]](<2 x s32>)
-    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32), [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CONCAT_VECTORS]](<4 x s32>)
+    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY]](<2 x s32>)
     ; CHECK: [[ZEXT:%[0-9]+]]:_(s64) = G_ZEXT [[UV]](s32)
     ; CHECK: [[ZEXT1:%[0-9]+]]:_(s64) = G_ZEXT [[UV1]](s32)
+    ; CHECK: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY1]](<2 x s32>)
     ; CHECK: [[ZEXT2:%[0-9]+]]:_(s64) = G_ZEXT [[UV2]](s32)
     ; CHECK: [[ZEXT3:%[0-9]+]]:_(s64) = G_ZEXT [[UV3]](s32)
-    ; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<4 x s64>) = G_BUILD_VECTOR [[ZEXT]](s64), [[ZEXT1]](s64), [[ZEXT2]](s64), [[ZEXT3]](s64)
-    ; CHECK: [[UV4:%[0-9]+]]:_(s64), [[UV5:%[0-9]+]]:_(s64), [[UV6:%[0-9]+]]:_(s64), [[UV7:%[0-9]+]]:_(s64) = G_UNMERGE_VALUES [[BUILD_VECTOR]](<4 x s64>)
-    ; CHECK: S_ENDPGM 0, implicit [[UV4]](s64), implicit [[UV5]](s64), implicit [[UV6]](s64), implicit [[UV7]](s64)
+    ; CHECK: S_ENDPGM 0, implicit [[ZEXT]](s64), implicit [[ZEXT1]](s64), implicit [[ZEXT2]](s64), implicit [[ZEXT3]](s64)
     %0:_(<2 x s32>) = COPY $vgpr0_vgpr1
     %1:_(<2 x s32>) = COPY $vgpr2_vgpr3
     %2:_(<4 x s32>) = G_CONCAT_VECTORS %0, %1
@@ -376,15 +383,13 @@
     ; CHECK-LABEL: name: test_unmerge_values_s64_of_anyext_concat_vectors_v2s32_v2s32
     ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr0_vgpr1
     ; CHECK: [[COPY1:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr2_vgpr3
-    ; CHECK: [[CONCAT_VECTORS:%[0-9]+]]:_(<4 x s32>) = G_CONCAT_VECTORS [[COPY]](<2 x s32>), [[COPY1]](<2 x s32>)
-    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32), [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CONCAT_VECTORS]](<4 x s32>)
+    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY]](<2 x s32>)
     ; CHECK: [[ANYEXT:%[0-9]+]]:_(s64) = G_ANYEXT [[UV]](s32)
     ; CHECK: [[ANYEXT1:%[0-9]+]]:_(s64) = G_ANYEXT [[UV1]](s32)
+    ; CHECK: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY1]](<2 x s32>)
     ; CHECK: [[ANYEXT2:%[0-9]+]]:_(s64) = G_ANYEXT [[UV2]](s32)
     ; CHECK: [[ANYEXT3:%[0-9]+]]:_(s64) = G_ANYEXT [[UV3]](s32)
-    ; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<4 x s64>) = G_BUILD_VECTOR [[ANYEXT]](s64), [[ANYEXT1]](s64), [[ANYEXT2]](s64), [[ANYEXT3]](s64)
-    ; CHECK: [[UV4:%[0-9]+]]:_(s64), [[UV5:%[0-9]+]]:_(s64), [[UV6:%[0-9]+]]:_(s64), [[UV7:%[0-9]+]]:_(s64) = G_UNMERGE_VALUES [[BUILD_VECTOR]](<4 x s64>)
-    ; CHECK: S_ENDPGM 0, implicit [[UV4]](s64), implicit [[UV5]](s64), implicit [[UV6]](s64), implicit [[UV7]](s64)
+    ; CHECK: S_ENDPGM 0, implicit [[ANYEXT]](s64), implicit [[ANYEXT1]](s64), implicit [[ANYEXT2]](s64), implicit [[ANYEXT3]](s64)
     %0:_(<2 x s32>) = COPY $vgpr0_vgpr1
     %1:_(<2 x s32>) = COPY $vgpr2_vgpr3
     %2:_(<4 x s32>) = G_CONCAT_VECTORS %0, %1
@@ -400,10 +405,13 @@
     ; CHECK-LABEL: name: test_unmerge_values_s8_of_trunc_v4s16_concat_vectors_v2s32_v2s32
     ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr0_vgpr1
     ; CHECK: [[COPY1:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr2_vgpr3
-    ; CHECK: [[CONCAT_VECTORS:%[0-9]+]]:_(<4 x s32>) = G_CONCAT_VECTORS [[COPY]](<2 x s32>), [[COPY1]](<2 x s32>)
-    ; CHECK: [[TRUNC:%[0-9]+]]:_(<4 x s16>) = G_TRUNC [[CONCAT_VECTORS]](<4 x s32>)
-    ; CHECK: [[UV:%[0-9]+]]:_(s8), [[UV1:%[0-9]+]]:_(s8), [[UV2:%[0-9]+]]:_(s8), [[UV3:%[0-9]+]]:_(s8), [[UV4:%[0-9]+]]:_(s8), [[UV5:%[0-9]+]]:_(s8), [[UV6:%[0-9]+]]:_(s8), [[UV7:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[TRUNC]](<4 x s16>)
-    ; CHECK: S_ENDPGM 0, implicit [[UV]](s8), implicit [[UV1]](s8), implicit [[UV2]](s8), implicit [[UV3]](s8), implicit [[UV4]](s8), implicit [[UV5]](s8), implicit [[UV6]](s8), implicit [[UV7]](s8)
+    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY]](<2 x s32>)
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s8) = G_TRUNC [[UV]](s32)
+    ; CHECK: [[TRUNC1:%[0-9]+]]:_(s8) = G_TRUNC [[UV1]](s32)
+    ; CHECK: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY1]](<2 x s32>)
+    ; CHECK: [[TRUNC2:%[0-9]+]]:_(s8) = G_TRUNC [[UV2]](s32)
+    ; CHECK: [[TRUNC3:%[0-9]+]]:_(s8) = G_TRUNC [[UV3]](s32)
+    ; CHECK: S_ENDPGM 0, implicit [[TRUNC]](s8), implicit [[TRUNC1]](s8), implicit %6:_(s8), implicit %7:_(s8), implicit [[TRUNC2]](s8), implicit [[TRUNC3]](s8), implicit %10:_(s8), implicit %11:_(s8)
     %0:_(<2 x s32>) = COPY $vgpr0_vgpr1
     %1:_(<2 x s32>) = COPY $vgpr2_vgpr3
     %2:_(<4 x s32>) = G_CONCAT_VECTORS %0, %1
@@ -419,8 +427,8 @@
     ; CHECK-LABEL: name: test_unmerge_values_s16_of_anyext_v4s64_concat_vectors_v2s32_v2s32
     ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr0_vgpr1
     ; CHECK: [[COPY1:%[0-9]+]]:_(<2 x s32>) = COPY $vgpr2_vgpr3
-    ; CHECK: [[CONCAT_VECTORS:%[0-9]+]]:_(<4 x s32>) = G_CONCAT_VECTORS [[COPY]](<2 x s32>), [[COPY1]](<2 x s32>)
-    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32), [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CONCAT_VECTORS]](<4 x s32>)
+    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY]](<2 x s32>)
+    ; CHECK: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY1]](<2 x s32>)
     ; CHECK: [[ANYEXT:%[0-9]+]]:_(s64) = G_ANYEXT [[UV]](s32)
     ; CHECK: [[ANYEXT1:%[0-9]+]]:_(s64) = G_ANYEXT [[UV1]](s32)
     ; CHECK: [[ANYEXT2:%[0-9]+]]:_(s64) = G_ANYEXT [[UV2]](s32)
Index: test/CodeGen/AMDGPU/GlobalISel/legalize-phi.mir
===================================================================
--- test/CodeGen/AMDGPU/GlobalISel/legalize-phi.mir
+++ test/CodeGen/AMDGPU/GlobalISel/legalize-phi.mir
@@ -522,7 +522,6 @@
   ; CHECK:   liveins: $vgpr0_vgpr1_vgpr2_vgpr3, $vgpr4
   ; CHECK:   [[DEF:%[0-9]+]]:_(<16 x s32>) = G_IMPLICIT_DEF
   ; CHECK:   [[DEF1:%[0-9]+]]:_(<16 x s32>) = G_IMPLICIT_DEF
-  ; CHECK:   [[CONCAT_VECTORS:%[0-9]+]]:_(<32 x s32>) = G_CONCAT_VECTORS [[DEF]](<16 x s32>), [[DEF1]](<16 x s32>)
   ; CHECK:   [[COPY:%[0-9]+]]:_(s32) = COPY $vgpr4
   ; CHECK:   [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 0
   ; CHECK:   [[ICMP:%[0-9]+]]:_(s1) = G_ICMP intpred(eq), [[COPY]](s32), [[C]]
@@ -530,8 +529,10 @@
   ; CHECK:   G_BR %bb.2
   ; CHECK: bb.1:
   ; CHECK:   successors: %bb.2(0x80000000)
-  ; CHECK:   [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32), [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32), [[UV4:%[0-9]+]]:_(s32), [[UV5:%[0-9]+]]:_(s32), [[UV6:%[0-9]+]]:_(s32), [[UV7:%[0-9]+]]:_(s32), [[UV8:%[0-9]+]]:_(s32), [[UV9:%[0-9]+]]:_(s32), [[UV10:%[0-9]+]]:_(s32), [[UV11:%[0-9]+]]:_(s32), [[UV12:%[0-9]+]]:_(s32), [[UV13:%[0-9]+]]:_(s32), [[UV14:%[0-9]+]]:_(s32), [[UV15:%[0-9]+]]:_(s32), [[UV16:%[0-9]+]]:_(s32), [[UV17:%[0-9]+]]:_(s32), [[UV18:%[0-9]+]]:_(s32), [[UV19:%[0-9]+]]:_(s32), [[UV20:%[0-9]+]]:_(s32), [[UV21:%[0-9]+]]:_(s32), [[UV22:%[0-9]+]]:_(s32), [[UV23:%[0-9]+]]:_(s32), [[UV24:%[0-9]+]]:_(s32), [[UV25:%[0-9]+]]:_(s32), [[UV26:%[0-9]+]]:_(s32), [[UV27:%[0-9]+]]:_(s32), [[UV28:%[0-9]+]]:_(s32), [[UV29:%[0-9]+]]:_(s32), [[UV30:%[0-9]+]]:_(s32), [[UV31:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CONCAT_VECTORS]](<32 x s32>)
-  ; CHECK:   [[UV32:%[0-9]+]]:_(s32), [[UV33:%[0-9]+]]:_(s32), [[UV34:%[0-9]+]]:_(s32), [[UV35:%[0-9]+]]:_(s32), [[UV36:%[0-9]+]]:_(s32), [[UV37:%[0-9]+]]:_(s32), [[UV38:%[0-9]+]]:_(s32), [[UV39:%[0-9]+]]:_(s32), [[UV40:%[0-9]+]]:_(s32), [[UV41:%[0-9]+]]:_(s32), [[UV42:%[0-9]+]]:_(s32), [[UV43:%[0-9]+]]:_(s32), [[UV44:%[0-9]+]]:_(s32), [[UV45:%[0-9]+]]:_(s32), [[UV46:%[0-9]+]]:_(s32), [[UV47:%[0-9]+]]:_(s32), [[UV48:%[0-9]+]]:_(s32), [[UV49:%[0-9]+]]:_(s32), [[UV50:%[0-9]+]]:_(s32), [[UV51:%[0-9]+]]:_(s32), [[UV52:%[0-9]+]]:_(s32), [[UV53:%[0-9]+]]:_(s32), [[UV54:%[0-9]+]]:_(s32), [[UV55:%[0-9]+]]:_(s32), [[UV56:%[0-9]+]]:_(s32), [[UV57:%[0-9]+]]:_(s32), [[UV58:%[0-9]+]]:_(s32), [[UV59:%[0-9]+]]:_(s32), [[UV60:%[0-9]+]]:_(s32), [[UV61:%[0-9]+]]:_(s32), [[UV62:%[0-9]+]]:_(s32), [[UV63:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CONCAT_VECTORS]](<32 x s32>)
+  ; CHECK:   [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32), [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32), [[UV4:%[0-9]+]]:_(s32), [[UV5:%[0-9]+]]:_(s32), [[UV6:%[0-9]+]]:_(s32), [[UV7:%[0-9]+]]:_(s32), [[UV8:%[0-9]+]]:_(s32), [[UV9:%[0-9]+]]:_(s32), [[UV10:%[0-9]+]]:_(s32), [[UV11:%[0-9]+]]:_(s32), [[UV12:%[0-9]+]]:_(s32), [[UV13:%[0-9]+]]:_(s32), [[UV14:%[0-9]+]]:_(s32), [[UV15:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[DEF]](<16 x s32>)
+  ; CHECK:   [[UV16:%[0-9]+]]:_(s32), [[UV17:%[0-9]+]]:_(s32), [[UV18:%[0-9]+]]:_(s32), [[UV19:%[0-9]+]]:_(s32), [[UV20:%[0-9]+]]:_(s32), [[UV21:%[0-9]+]]:_(s32), [[UV22:%[0-9]+]]:_(s32), [[UV23:%[0-9]+]]:_(s32), [[UV24:%[0-9]+]]:_(s32), [[UV25:%[0-9]+]]:_(s32), [[UV26:%[0-9]+]]:_(s32), [[UV27:%[0-9]+]]:_(s32), [[UV28:%[0-9]+]]:_(s32), [[UV29:%[0-9]+]]:_(s32), [[UV30:%[0-9]+]]:_(s32), [[UV31:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[DEF1]](<16 x s32>)
+  ; CHECK:   [[UV32:%[0-9]+]]:_(s32), [[UV33:%[0-9]+]]:_(s32), [[UV34:%[0-9]+]]:_(s32), [[UV35:%[0-9]+]]:_(s32), [[UV36:%[0-9]+]]:_(s32), [[UV37:%[0-9]+]]:_(s32), [[UV38:%[0-9]+]]:_(s32), [[UV39:%[0-9]+]]:_(s32), [[UV40:%[0-9]+]]:_(s32), [[UV41:%[0-9]+]]:_(s32), [[UV42:%[0-9]+]]:_(s32), [[UV43:%[0-9]+]]:_(s32), [[UV44:%[0-9]+]]:_(s32), [[UV45:%[0-9]+]]:_(s32), [[UV46:%[0-9]+]]:_(s32), [[UV47:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[DEF]](<16 x s32>)
+  ; CHECK:   [[UV48:%[0-9]+]]:_(s32), [[UV49:%[0-9]+]]:_(s32), [[UV50:%[0-9]+]]:_(s32), [[UV51:%[0-9]+]]:_(s32), [[UV52:%[0-9]+]]:_(s32), [[UV53:%[0-9]+]]:_(s32), [[UV54:%[0-9]+]]:_(s32), [[UV55:%[0-9]+]]:_(s32), [[UV56:%[0-9]+]]:_(s32), [[UV57:%[0-9]+]]:_(s32), [[UV58:%[0-9]+]]:_(s32), [[UV59:%[0-9]+]]:_(s32), [[UV60:%[0-9]+]]:_(s32), [[UV61:%[0-9]+]]:_(s32), [[UV62:%[0-9]+]]:_(s32), [[UV63:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[DEF1]](<16 x s32>)
   ; CHECK:   [[ADD:%[0-9]+]]:_(s32) = G_ADD [[UV]], [[UV32]]
   ; CHECK:   [[ADD1:%[0-9]+]]:_(s32) = G_ADD [[UV1]], [[UV33]]
   ; CHECK:   [[ADD2:%[0-9]+]]:_(s32) = G_ADD [[UV2]], [[UV34]]
@@ -570,8 +571,8 @@
   ; CHECK: bb.2:
   ; CHECK:   [[PHI:%[0-9]+]]:_(<16 x s32>) = G_PHI [[DEF]](<16 x s32>), %bb.0, [[UV64]](<16 x s32>), %bb.1
   ; CHECK:   [[PHI1:%[0-9]+]]:_(<16 x s32>) = G_PHI [[DEF1]](<16 x s32>), %bb.0, [[UV65]](<16 x s32>), %bb.1
-  ; CHECK:   [[CONCAT_VECTORS1:%[0-9]+]]:_(<32 x s32>) = G_CONCAT_VECTORS [[PHI]](<16 x s32>), [[PHI1]](<16 x s32>)
-  ; CHECK:   S_SETPC_B64 undef $sgpr30_sgpr31, implicit [[CONCAT_VECTORS1]](<32 x s32>)
+  ; CHECK:   [[CONCAT_VECTORS:%[0-9]+]]:_(<32 x s32>) = G_CONCAT_VECTORS [[PHI]](<16 x s32>), [[PHI1]](<16 x s32>)
+  ; CHECK:   S_SETPC_B64 undef $sgpr30_sgpr31, implicit [[CONCAT_VECTORS]](<32 x s32>)
   bb.0:
     successors: %bb.1, %bb.2
     liveins: $vgpr0_vgpr1_vgpr2_vgpr3, $vgpr4