Index: lib/Transforms/Scalar/InferAddressSpaces.cpp
===================================================================
--- lib/Transforms/Scalar/InferAddressSpaces.cpp
+++ lib/Transforms/Scalar/InferAddressSpaces.cpp
@@ -192,6 +192,7 @@
   case Instruction::BitCast:
   case Instruction::AddrSpaceCast:
   case Instruction::GetElementPtr:
+  case Instruction::Select:
     return true;
   default:
     return false;
@@ -214,6 +215,8 @@
   case Instruction::AddrSpaceCast:
   case Instruction::GetElementPtr:
     return {Op.getOperand(0)};
+  case Instruction::Select:
+    return {Op.getOperand(1), Op.getOperand(2)};
   default:
     llvm_unreachable("Unexpected instruction type.");
   }
@@ -410,6 +413,11 @@
     NewGEP->setIsInBounds(GEP->isInBounds());
     return NewGEP;
   }
+  case Instruction::Select: {
+    assert(I->getType()->isPointerTy());
+    return SelectInst::Create(I->getOperand(0), NewPointerOperands[1],
+                              NewPointerOperands[2], "", nullptr, I);
+  }
   default:
     llvm_unreachable("Unexpected opcode");
   }
Index: test/Transforms/InferAddressSpaces/AMDGPU/select.ll
===================================================================
--- /dev/null
+++ test/Transforms/InferAddressSpaces/AMDGPU/select.ll
@@ -0,0 +1,165 @@
+; RUN: opt -S -mtriple=amdgcn-amd-amdhsa -infer-address-spaces %s | FileCheck %s
+
+; Instcombine pulls the addrspacecast out of the select, make sure
+;  this doesn't do something insane on non-canonical IR.
+
+; CHECK-LABEL: @return_select_group_flat(
+; CHECK-NEXT: %cast0 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+; CHECK-NEXT: %cast1 = addrspacecast i32 addrspace(3)* %group.ptr.1 to i32 addrspace(4)*
+; CHECK-NEXT: %select = select i1 %c, i32 addrspace(4)* %cast0, i32 addrspace(4)* %cast1
+; CHECK-NEXT: ret i32 addrspace(4)* %select
+define i32 addrspace(4)* @return_select_group_flat(i1 %c, i32 addrspace(3)* %group.ptr.0, i32 addrspace(3)* %group.ptr.1) #0 {
+  %cast0 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+  %cast1 = addrspacecast i32 addrspace(3)* %group.ptr.1 to i32 addrspace(4)*
+  %select = select i1 %c, i32 addrspace(4)* %cast0, i32 addrspace(4)* %cast1
+  ret i32 addrspace(4)* %select
+}
+
+; CHECK-LABEL: @store_select_group_flat(
+; CHECK: %select = select i1 %c, i32 addrspace(3)* %group.ptr.0, i32 addrspace(3)* %group.ptr.1
+; CHECK: store i32 -1, i32 addrspace(3)* %select
+define void @store_select_group_flat(i1 %c, i32 addrspace(3)* %group.ptr.0, i32 addrspace(3)* %group.ptr.1) #0 {
+  %cast0 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+  %cast1 = addrspacecast i32 addrspace(3)* %group.ptr.1 to i32 addrspace(4)*
+  %select = select i1 %c, i32 addrspace(4)* %cast0, i32 addrspace(4)* %cast1
+  store i32 -1, i32 addrspace(4)* %select
+  ret void
+}
+
+; Make sure metadata is preserved
+; CHECK-LABEL: @load_select_group_flat_md(
+; CHECK: %select = select i1 %c, i32 addrspace(3)* %group.ptr.0, i32 addrspace(3)* %group.ptr.1, !prof !0
+; CHECK: %load = load i32, i32 addrspace(3)* %select
+define i32 @load_select_group_flat_md(i1 %c, i32 addrspace(3)* %group.ptr.0, i32 addrspace(3)* %group.ptr.1) #0 {
+  %cast0 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+  %cast1 = addrspacecast i32 addrspace(3)* %group.ptr.1 to i32 addrspace(4)*
+  %select = select i1 %c, i32 addrspace(4)* %cast0, i32 addrspace(4)* %cast1, !prof !0
+  %load = load i32, i32 addrspace(4)* %select
+  ret i32 %load
+}
+
+; CHECK-LABEL: @store_select_mismatch_group_private_flat(
+; CHECK: %1 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+; CHECK: %2 = addrspacecast i32* %private.ptr.1 to i32 addrspace(4)*
+; CHECK: %select = select i1 %c, i32 addrspace(4)* %1, i32 addrspace(4)* %2
+; CHECK: store i32 -1, i32 addrspace(4)* %select
+define void @store_select_mismatch_group_private_flat(i1 %c, i32 addrspace(3)* %group.ptr.0, i32* %private.ptr.1) #0 {
+  %cast0 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+  %cast1 = addrspacecast i32* %private.ptr.1 to i32 addrspace(4)*
+  %select = select i1 %c, i32 addrspace(4)* %cast0, i32 addrspace(4)* %cast1
+  store i32 -1, i32 addrspace(4)* %select
+  ret void
+}
+
+@lds0 = internal addrspace(3) global i32 123, align 4
+@lds1 = internal addrspace(3) global i32 456, align 4
+
+; CHECK-LABEL: @constexpr_select_group_flat(
+; CHCK: %tmp = load i32, i32 addrspace(3)* select (i1 icmp eq (i32 ptrtoint (i32 addrspace(3)* @lds1 to i32), i32 4), i32 addrspace(3)* @lds0, i32 addrspace(3)* @lds1)
+define i32 @constexpr_select_group_flat() #0 {
+bb:
+  %tmp = load i32, i32 addrspace(4)* select (i1 icmp eq (i32 ptrtoint (i32 addrspace(3)* @lds1 to i32), i32 4), i32 addrspace(4)* addrspacecast (i32 addrspace(3)* @lds0 to i32 addrspace(4)*), i32 addrspace(4)* addrspacecast (i32 addrspace(3)* @lds1 to i32 addrspace(4)*))
+  ret i32 %tmp
+}
+
+; FIXME: Should be able to cast the constants
+; CHECK-LABEL: @store_select_group_flat_null(
+; CHECK: %1 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+; CHECK: %select = select i1 %c, i32 addrspace(4)* %1, i32 addrspace(4)* null
+; CHECK: store i32 -1, i32 addrspace(4)* %select
+define void @store_select_group_flat_null(i1 %c, i32 addrspace(3)* %group.ptr.0) #0 {
+  %cast0 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+  %select = select i1 %c, i32 addrspace(4)* %cast0, i32 addrspace(4)* null
+  store i32 -1, i32 addrspace(4)* %select
+  ret void
+}
+
+; CHECK-LABEL: @store_select_group_flat_null_swap(
+; CHECK: %1 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+; CHECK: %select = select i1 %c, i32 addrspace(4)* null, i32 addrspace(4)* %1
+; CHECK: store i32 -1, i32 addrspace(4)* %select
+define void @store_select_group_flat_null_swap(i1 %c, i32 addrspace(3)* %group.ptr.0) #0 {
+  %cast0 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+  %select = select i1 %c, i32 addrspace(4)* null, i32 addrspace(4)* %cast0
+  store i32 -1, i32 addrspace(4)* %select
+  ret void
+}
+
+
+; CHECK-LABEL: @store_select_group_flat_undef(
+; CHECK: %1 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+; CHECK: %select = select i1 %c, i32 addrspace(4)* %1, i32 addrspace(4)* undef
+; CHECK: store i32 -1, i32 addrspace(4)* %select
+define void @store_select_group_flat_undef(i1 %c, i32 addrspace(3)* %group.ptr.0) #0 {
+  %cast0 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+  %select = select i1 %c, i32 addrspace(4)* %cast0, i32 addrspace(4)* undef
+  store i32 -1, i32 addrspace(4)* %select
+  ret void
+}
+
+; CHECK-LABEL: @store_select_group_flat_undef_swap(
+; CHECK: %1 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+; CHECK: %select = select i1 %c, i32 addrspace(4)* undef, i32 addrspace(4)* %1
+; CHECK: store i32 -1, i32 addrspace(4)* %select
+define void @store_select_group_flat_undef_swap(i1 %c, i32 addrspace(3)* %group.ptr.0) #0 {
+  %cast0 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+  %select = select i1 %c, i32 addrspace(4)* undef, i32 addrspace(4)* %cast0
+  store i32 -1, i32 addrspace(4)* %select
+  ret void
+}
+
+@global0 = internal addrspace(1) global i32 123, align 4
+
+; CHECK-LABEL: @store_select_group_flat_constexpr(
+; CHECK: %select = select i1 %c, i32 addrspace(3)* %group.ptr.0, i32 addrspace(3)* @lds1
+; CHECK: store i32 7, i32 addrspace(3)* %select
+define void @store_select_group_flat_constexpr(i1 %c, i32 addrspace(3)* %group.ptr.0) #0 {
+  %cast0 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+  %select = select i1 %c, i32 addrspace(4)* %cast0, i32 addrspace(4)* addrspacecast (i32 addrspace(3)* @lds1 to i32 addrspace(4)*)
+  store i32 7, i32 addrspace(4)* %select
+  ret void
+}
+
+; CHECK-LABEL: @store_select_group_global_mismatch_flat_constexpr(
+; CHECK: %1 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+; CHECK: %select = select i1 %c, i32 addrspace(4)* %1, i32 addrspace(4)* addrspacecast (i32 addrspace(1)* @global0 to i32 addrspace(4)*)
+; CHECK: store i32 7, i32 addrspace(4)* %select
+define void @store_select_group_global_mismatch_flat_constexpr(i1 %c, i32 addrspace(3)* %group.ptr.0) #0 {
+  %cast0 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+  %select = select i1 %c, i32 addrspace(4)* %cast0, i32 addrspace(4)* addrspacecast (i32 addrspace(1)* @global0 to i32 addrspace(4)*)
+  store i32 7, i32 addrspace(4)* %select
+  ret void
+}
+
+; CHECK-LABEL: @store_select_group_global_mismatch_flat_constexpr_swap(
+; CHECK: %1 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+; CHECK: %select = select i1 %c, i32 addrspace(4)* addrspacecast (i32 addrspace(1)* @global0 to i32 addrspace(4)*), i32 addrspace(4)* %1
+; CHECK: store i32 7, i32 addrspace(4)* %select
+define void @store_select_group_global_mismatch_flat_constexpr_swap(i1 %c, i32 addrspace(3)* %group.ptr.0) #0 {
+  %cast0 = addrspacecast i32 addrspace(3)* %group.ptr.0 to i32 addrspace(4)*
+  %select = select i1 %c, i32 addrspace(4)* addrspacecast (i32 addrspace(1)* @global0 to i32 addrspace(4)*), i32 addrspace(4)* %cast0
+  store i32 7, i32 addrspace(4)* %select
+  ret void
+}
+
+; CHECK-LABEL: @store_select_group_flat_vector(
+; CHECK: %cast0 = addrspacecast <2 x i32 addrspace(3)*> %group.ptr.0 to <2 x i32 addrspace(4)*>
+; CHECK: %cast1 = addrspacecast <2 x i32 addrspace(3)*> %group.ptr.1 to <2 x i32 addrspace(4)*>
+; CHECK: %select = select i1 %c, <2 x i32 addrspace(4)*> %cast0, <2 x i32 addrspace(4)*> %cast1
+; CHECK: %extract0 = extractelement <2 x i32 addrspace(4)*> %select, i32 0
+; CHECK: %extract1 = extractelement <2 x i32 addrspace(4)*> %select, i32 1
+; CHECK: store i32 -1, i32 addrspace(4)* %extract0
+; CHECK: store i32 -2, i32 addrspace(4)* %extract1
+define void @store_select_group_flat_vector(i1 %c, <2 x i32 addrspace(3)*> %group.ptr.0, <2 x i32 addrspace(3)*> %group.ptr.1) #0 {
+  %cast0 = addrspacecast <2 x i32 addrspace(3)*> %group.ptr.0 to <2 x i32 addrspace(4)*>
+  %cast1 = addrspacecast <2 x i32 addrspace(3)*> %group.ptr.1 to <2 x i32 addrspace(4)*>
+  %select = select i1 %c, <2 x i32 addrspace(4)*> %cast0, <2 x i32 addrspace(4)*> %cast1
+  %extract0 = extractelement <2 x i32 addrspace(4)*> %select, i32 0
+  %extract1 = extractelement <2 x i32 addrspace(4)*> %select, i32 1
+  store i32 -1, i32 addrspace(4)* %extract0
+  store i32 -2, i32 addrspace(4)* %extract1
+  ret void
+}
+attributes #0 = { nounwind }
+
+!0 = !{!"branch_weights", i32 2, i32 10}