Index: lib/CodeGen/GlobalISel/LegalizerHelper.cpp
===================================================================
--- lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -2363,6 +2363,18 @@
     moreElementsVectorSrc(MI, MoreTy, 1);
     Observer.changedInstr(MI);
     return Legalized;
+  case TargetOpcode::G_SELECT:
+    if (TypeIdx != 0)
+      return UnableToLegalize;
+    if (MRI.getType(MI.getOperand(1).getReg()).isVector())
+      return UnableToLegalize;
+
+    Observer.changingInstr(MI);
+    moreElementsVectorSrc(MI, MoreTy, 2);
+    moreElementsVectorSrc(MI, MoreTy, 3);
+    moreElementsVectorDst(MI, MoreTy, 0);
+    Observer.changedInstr(MI);
+    return Legalized;
   default:
     return UnableToLegalize;
   }
Index: lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
+++ lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
@@ -71,6 +71,12 @@
   };
 }
 
+static LegalityPredicate numElementsNotEven(unsigned TypeIdx) {
+  return [=](const LegalityQuery &Query) {
+    const LLT QueryTy = Query.Types[TypeIdx];
+    return QueryTy.isVector() && QueryTy.getNumElements() % 2 != 0;
+  };
+}
 
 AMDGPULegalizerInfo::AMDGPULegalizerInfo(const GCNSubtarget &ST,
                                          const GCNTargetMachine &TM) {
@@ -458,28 +464,13 @@
           GlobalPtr, LocalPtr, FlatPtr, PrivatePtr,
           LLT::vector(2, LocalPtr), LLT::vector(2, PrivatePtr)}, {S1})
     .clampScalar(0, S32, S64)
-    .fewerElementsIf(
-      [=](const LegalityQuery &Query) {
-        if (Query.Types[1].isVector())
-          return true;
-
-        LLT Ty = Query.Types[0];
-
-        // FIXME: Hack until odd splits handled
-        return Ty.isVector() &&
-          (Ty.getScalarSizeInBits() > 32 || Ty.getNumElements() % 2 != 0);
-      },
-      scalarize(0))
-    // FIXME: Handle 16-bit vectors better
-    .fewerElementsIf(
-      [=](const LegalityQuery &Query) {
-        return Query.Types[0].isVector() &&
-               Query.Types[0].getElementType().getSizeInBits() < 32;},
-      scalarize(0))
+    .moreElementsIf(isSmallOddVector(0), oneMoreElement(0))
+    .fewerElementsIf(numElementsNotEven(0), scalarize(0))
     .scalarize(1)
     .clampMaxNumElements(0, S32, 2)
     .clampMaxNumElements(0, LocalPtr, 2)
     .clampMaxNumElements(0, PrivatePtr, 2)
+    .scalarize(0)
     .legalIf(all(isPointer(0), typeIs(1, S1)));
 
   // TODO: Only the low 4/5/6 bits of the shift amount are observed, so we can
Index: test/CodeGen/AMDGPU/GlobalISel/legalize-select.mir
===================================================================
--- test/CodeGen/AMDGPU/GlobalISel/legalize-select.mir
+++ test/CodeGen/AMDGPU/GlobalISel/legalize-select.mir
@@ -248,23 +248,32 @@
     ; CHECK: [[TRUNC:%[0-9]+]]:_(<3 x s8>) = G_TRUNC [[COPY1]](<3 x s32>)
     ; CHECK: [[TRUNC1:%[0-9]+]]:_(<3 x s8>) = G_TRUNC [[COPY2]](<3 x s32>)
     ; CHECK: [[ICMP:%[0-9]+]]:_(s1) = G_ICMP intpred(ne), [[COPY]](s32), [[C]]
-    ; CHECK: [[UV:%[0-9]+]]:_(s8), [[UV1:%[0-9]+]]:_(s8), [[UV2:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[TRUNC]](<3 x s8>)
-    ; CHECK: [[UV3:%[0-9]+]]:_(s8), [[UV4:%[0-9]+]]:_(s8), [[UV5:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[TRUNC1]](<3 x s8>)
+    ; CHECK: [[DEF:%[0-9]+]]:_(<4 x s8>) = G_IMPLICIT_DEF
+    ; CHECK: [[INSERT:%[0-9]+]]:_(<4 x s8>) = G_INSERT [[DEF]], [[TRUNC]](<3 x s8>), 0
+    ; CHECK: [[DEF1:%[0-9]+]]:_(<4 x s8>) = G_IMPLICIT_DEF
+    ; CHECK: [[INSERT1:%[0-9]+]]:_(<4 x s8>) = G_INSERT [[DEF1]], [[TRUNC1]](<3 x s8>), 0
+    ; CHECK: [[UV:%[0-9]+]]:_(s8), [[UV1:%[0-9]+]]:_(s8), [[UV2:%[0-9]+]]:_(s8), [[UV3:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[INSERT]](<4 x s8>)
+    ; CHECK: [[UV4:%[0-9]+]]:_(s8), [[UV5:%[0-9]+]]:_(s8), [[UV6:%[0-9]+]]:_(s8), [[UV7:%[0-9]+]]:_(s8) = G_UNMERGE_VALUES [[INSERT1]](<4 x s8>)
     ; CHECK: [[ANYEXT:%[0-9]+]]:_(s32) = G_ANYEXT [[UV]](s8)
-    ; CHECK: [[ANYEXT1:%[0-9]+]]:_(s32) = G_ANYEXT [[UV3]](s8)
+    ; CHECK: [[ANYEXT1:%[0-9]+]]:_(s32) = G_ANYEXT [[UV4]](s8)
     ; CHECK: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[ANYEXT]], [[ANYEXT1]]
     ; CHECK: [[TRUNC2:%[0-9]+]]:_(s8) = G_TRUNC [[SELECT]](s32)
     ; CHECK: [[ANYEXT2:%[0-9]+]]:_(s32) = G_ANYEXT [[UV1]](s8)
-    ; CHECK: [[ANYEXT3:%[0-9]+]]:_(s32) = G_ANYEXT [[UV4]](s8)
+    ; CHECK: [[ANYEXT3:%[0-9]+]]:_(s32) = G_ANYEXT [[UV5]](s8)
     ; CHECK: [[SELECT1:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[ANYEXT2]], [[ANYEXT3]]
     ; CHECK: [[TRUNC3:%[0-9]+]]:_(s8) = G_TRUNC [[SELECT1]](s32)
     ; CHECK: [[ANYEXT4:%[0-9]+]]:_(s32) = G_ANYEXT [[UV2]](s8)
-    ; CHECK: [[ANYEXT5:%[0-9]+]]:_(s32) = G_ANYEXT [[UV5]](s8)
+    ; CHECK: [[ANYEXT5:%[0-9]+]]:_(s32) = G_ANYEXT [[UV6]](s8)
     ; CHECK: [[SELECT2:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[ANYEXT4]], [[ANYEXT5]]
     ; CHECK: [[TRUNC4:%[0-9]+]]:_(s8) = G_TRUNC [[SELECT2]](s32)
-    ; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<3 x s8>) = G_BUILD_VECTOR [[TRUNC2]](s8), [[TRUNC3]](s8), [[TRUNC4]](s8)
-    ; CHECK: [[ANYEXT6:%[0-9]+]]:_(<3 x s32>) = G_ANYEXT [[BUILD_VECTOR]](<3 x s8>)
-    ; CHECK: $vgpr0_vgpr1_vgpr2 = COPY [[ANYEXT6]](<3 x s32>)
+    ; CHECK: [[ANYEXT6:%[0-9]+]]:_(s32) = G_ANYEXT [[UV3]](s8)
+    ; CHECK: [[ANYEXT7:%[0-9]+]]:_(s32) = G_ANYEXT [[UV7]](s8)
+    ; CHECK: [[SELECT3:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[ANYEXT6]], [[ANYEXT7]]
+    ; CHECK: [[TRUNC5:%[0-9]+]]:_(s8) = G_TRUNC [[SELECT3]](s32)
+    ; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<4 x s8>) = G_BUILD_VECTOR [[TRUNC2]](s8), [[TRUNC3]](s8), [[TRUNC4]](s8), [[TRUNC5]](s8)
+    ; CHECK: [[EXTRACT:%[0-9]+]]:_(<3 x s8>) = G_EXTRACT [[BUILD_VECTOR]](<4 x s8>), 0
+    ; CHECK: [[ANYEXT8:%[0-9]+]]:_(<3 x s32>) = G_ANYEXT [[EXTRACT]](<3 x s8>)
+    ; CHECK: $vgpr0_vgpr1_vgpr2 = COPY [[ANYEXT8]](<3 x s32>)
     %0:_(s32) = COPY $vgpr0
     %1:_(s32) = G_CONSTANT i32 0
     %2:_(<3 x s32>) = COPY $vgpr1_vgpr2_vgpr3
@@ -365,24 +374,15 @@
     ; CHECK: [[ICMP:%[0-9]+]]:_(s1) = G_ICMP intpred(ne), [[COPY]](s32), [[C]]
     ; CHECK: [[EXTRACT:%[0-9]+]]:_(<3 x s16>) = G_EXTRACT [[COPY1]](<4 x s16>), 0
     ; CHECK: [[EXTRACT1:%[0-9]+]]:_(<3 x s16>) = G_EXTRACT [[COPY2]](<4 x s16>), 0
-    ; CHECK: [[UV:%[0-9]+]]:_(s16), [[UV1:%[0-9]+]]:_(s16), [[UV2:%[0-9]+]]:_(s16) = G_UNMERGE_VALUES [[EXTRACT]](<3 x s16>)
-    ; CHECK: [[UV3:%[0-9]+]]:_(s16), [[UV4:%[0-9]+]]:_(s16), [[UV5:%[0-9]+]]:_(s16) = G_UNMERGE_VALUES [[EXTRACT1]](<3 x s16>)
-    ; CHECK: [[ANYEXT:%[0-9]+]]:_(s32) = G_ANYEXT [[UV]](s16)
-    ; CHECK: [[ANYEXT1:%[0-9]+]]:_(s32) = G_ANYEXT [[UV3]](s16)
-    ; CHECK: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[ANYEXT]], [[ANYEXT1]]
-    ; CHECK: [[TRUNC:%[0-9]+]]:_(s16) = G_TRUNC [[SELECT]](s32)
-    ; CHECK: [[ANYEXT2:%[0-9]+]]:_(s32) = G_ANYEXT [[UV1]](s16)
-    ; CHECK: [[ANYEXT3:%[0-9]+]]:_(s32) = G_ANYEXT [[UV4]](s16)
-    ; CHECK: [[SELECT1:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[ANYEXT2]], [[ANYEXT3]]
-    ; CHECK: [[TRUNC1:%[0-9]+]]:_(s16) = G_TRUNC [[SELECT1]](s32)
-    ; CHECK: [[ANYEXT4:%[0-9]+]]:_(s32) = G_ANYEXT [[UV2]](s16)
-    ; CHECK: [[ANYEXT5:%[0-9]+]]:_(s32) = G_ANYEXT [[UV5]](s16)
-    ; CHECK: [[SELECT2:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[ANYEXT4]], [[ANYEXT5]]
-    ; CHECK: [[TRUNC2:%[0-9]+]]:_(s16) = G_TRUNC [[SELECT2]](s32)
-    ; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<3 x s16>) = G_BUILD_VECTOR [[TRUNC]](s16), [[TRUNC1]](s16), [[TRUNC2]](s16)
     ; CHECK: [[DEF:%[0-9]+]]:_(<4 x s16>) = G_IMPLICIT_DEF
-    ; CHECK: [[INSERT:%[0-9]+]]:_(<4 x s16>) = G_INSERT [[DEF]], [[BUILD_VECTOR]](<3 x s16>), 0
-    ; CHECK: $vgpr0_vgpr1 = COPY [[INSERT]](<4 x s16>)
+    ; CHECK: [[INSERT:%[0-9]+]]:_(<4 x s16>) = G_INSERT [[DEF]], [[EXTRACT]](<3 x s16>), 0
+    ; CHECK: [[DEF1:%[0-9]+]]:_(<4 x s16>) = G_IMPLICIT_DEF
+    ; CHECK: [[INSERT1:%[0-9]+]]:_(<4 x s16>) = G_INSERT [[DEF1]], [[EXTRACT1]](<3 x s16>), 0
+    ; CHECK: [[SELECT:%[0-9]+]]:_(<4 x s16>) = G_SELECT [[ICMP]](s1), [[INSERT]], [[INSERT1]]
+    ; CHECK: [[EXTRACT2:%[0-9]+]]:_(<3 x s16>) = G_EXTRACT [[SELECT]](<4 x s16>), 0
+    ; CHECK: [[DEF2:%[0-9]+]]:_(<4 x s16>) = G_IMPLICIT_DEF
+    ; CHECK: [[INSERT2:%[0-9]+]]:_(<4 x s16>) = G_INSERT [[DEF2]], [[EXTRACT2]](<3 x s16>), 0
+    ; CHECK: $vgpr0_vgpr1 = COPY [[INSERT2]](<4 x s16>)
     %0:_(s32) = COPY $vgpr0
     %1:_(<4 x s16>) = COPY $vgpr1_vgpr2
     %2:_(<4 x s16>) = COPY $vgpr3_vgpr4