Index: llvm/lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp
+++ llvm/lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp
@@ -1828,6 +1828,18 @@
       constrainOpWithReadfirstlane(MI, MRI, 3); // Index
       return;
     }
+    case Intrinsic::amdgcn_interp_p1:
+    case Intrinsic::amdgcn_interp_p2:
+    case Intrinsic::amdgcn_interp_mov:
+    case Intrinsic::amdgcn_interp_p1_f16:
+    case Intrinsic::amdgcn_interp_p2_f16: {
+      applyDefaultMapping(OpdMapper);
+
+      // Readlane for m0 value, which is always the last operand.
+      // FIXME: Should this be a waterfall loop instead?
+      constrainOpWithReadfirstlane(MI, MRI, MI.getNumOperands() - 1); // Index
+      return;
+    }
     default:
       break;
     }
@@ -2133,6 +2145,9 @@
 /// in RegBankSelect::Mode::Fast.  Any mapping that would cause a
 /// VGPR to SGPR generated is illegal.
 ///
+// Operands that must be SGPRs must accept potentially divergent VGPRs as
+// legal. These will be dealt with in applyMappingImpl.
+//
 const RegisterBankInfo::InstructionMapping &
 AMDGPURegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
   const MachineFunction &MF = *MI.getParent()->getParent();
@@ -2783,6 +2798,25 @@
       OpdsMapping[4] = getAGPROpMapping(MI.getOperand(4).getReg(), MRI, *TRI);
       break;
     }
+    case Intrinsic::amdgcn_interp_p1:
+    case Intrinsic::amdgcn_interp_p2:
+    case Intrinsic::amdgcn_interp_mov:
+    case Intrinsic::amdgcn_interp_p1_f16:
+    case Intrinsic::amdgcn_interp_p2_f16: {
+      const int M0Idx = MI.getNumOperands() - 1;
+      Register M0Reg = MI.getOperand(M0Idx).getReg();
+      unsigned M0Bank = getRegBankID(M0Reg, MRI, *TRI, AMDGPU::SGPRRegBankID);
+      unsigned DstSize = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits();
+
+      OpdsMapping[0] = AMDGPU::getValueMapping(AMDGPU::VGPRRegBankID, DstSize);
+      for (int I = 2; I != M0Idx && MI.getOperand(I).isReg(); ++I)
+        OpdsMapping[I] = AMDGPU::getValueMapping(AMDGPU::VGPRRegBankID, 32);
+
+      // Must be SGPR, but we must take whatever the original bank is and fix it
+      // later.
+      OpdsMapping[M0Idx] = AMDGPU::getValueMapping(M0Bank, 32);
+      break;
+    }
     }
     break;
   }
Index: llvm/test/CodeGen/AMDGPU/GlobalISel/regbankselect-amdgcn.interp.mov.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AMDGPU/GlobalISel/regbankselect-amdgcn.interp.mov.mir
@@ -0,0 +1,42 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -march=amdgcn -mcpu=fiji -run-pass=regbankselect -regbankselect-fast -verify-machineinstrs -o - %s | FileCheck %s
+# RUN: llc -march=amdgcn -mcpu=fiji -run-pass=regbankselect -regbankselect-greedy -verify-machineinstrs -o - %s | FileCheck %s
+
+---
+name: interp_mov_ss
+legalized: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0, $sgpr1
+    ; CHECK-LABEL: name: interp_mov_ss
+    ; CHECK: liveins: $sgpr0, $sgpr1
+    ; CHECK: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:sgpr(s32) = COPY $sgpr1
+    ; CHECK: [[COPY2:%[0-9]+]]:vgpr(s32) = COPY [[COPY]](s32)
+    ; CHECK: [[INT:%[0-9]+]]:vgpr(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.mov), [[COPY2]](s32), 1, 1, [[COPY1]](s32)
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s32) = COPY $sgpr1
+    %2:_(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.mov), %0, 1, 1, %1
+...
+
+---
+name: interp_mov_sv
+legalized: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0, $vgpr0
+    ; CHECK-LABEL: name: interp_mov_sv
+    ; CHECK: liveins: $sgpr0, $vgpr0
+    ; CHECK: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:vgpr_32(s32) = COPY $vgpr0
+    ; CHECK: [[COPY2:%[0-9]+]]:vgpr(s32) = COPY [[COPY]](s32)
+    ; CHECK: [[V_READFIRSTLANE_B32_:%[0-9]+]]:sreg_32 = V_READFIRSTLANE_B32 [[COPY1]](s32), implicit $exec
+    ; CHECK: [[INT:%[0-9]+]]:vgpr(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.mov), [[COPY2]](s32), 1, 1, [[V_READFIRSTLANE_B32_]]
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s32) = COPY $vgpr0
+    %2:_(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.mov), %0, 1, 1, %1
+...
Index: llvm/test/CodeGen/AMDGPU/GlobalISel/regbankselect-amdgcn.interp.p1.f16.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AMDGPU/GlobalISel/regbankselect-amdgcn.interp.p1.f16.mir
@@ -0,0 +1,43 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -march=amdgcn -mcpu=fiji -run-pass=regbankselect -regbankselect-fast -verify-machineinstrs -o - %s | FileCheck %s
+# RUN: llc -march=amdgcn -mcpu=fiji -run-pass=regbankselect -regbankselect-greedy -verify-machineinstrs -o - %s | FileCheck %s
+
+---
+name: interp_p1_f16_ss
+legalized: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0, $sgpr1
+
+    ; CHECK-LABEL: name: interp_p1_f16_ss
+    ; CHECK: liveins: $sgpr0, $sgpr1
+    ; CHECK: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:sgpr(s32) = COPY $sgpr1
+    ; CHECK: [[COPY2:%[0-9]+]]:vgpr(s32) = COPY [[COPY]](s32)
+    ; CHECK: [[INT:%[0-9]+]]:vgpr(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p1.f16), [[COPY2]](s32), 1, 1, 1, [[COPY1]](s32)
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s32) = COPY $sgpr1
+    %2:_(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p1.f16), %0, 1, 1, 1, %1
+...
+
+---
+name: interp_p1_f16_sv
+legalized: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0, $vgpr0
+    ; CHECK-LABEL: name: interp_p1_f16_sv
+    ; CHECK: liveins: $sgpr0, $vgpr0
+    ; CHECK: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:vgpr_32(s32) = COPY $vgpr0
+    ; CHECK: [[COPY2:%[0-9]+]]:vgpr(s32) = COPY [[COPY]](s32)
+    ; CHECK: [[V_READFIRSTLANE_B32_:%[0-9]+]]:sreg_32 = V_READFIRSTLANE_B32 [[COPY1]](s32), implicit $exec
+    ; CHECK: [[INT:%[0-9]+]]:vgpr(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p1.f16), [[COPY2]](s32), 1, 1, 1, [[V_READFIRSTLANE_B32_]]
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s32) = COPY $vgpr0
+    %2:_(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p1.f16), %0, 1, 1, 1, %1
+...
Index: llvm/test/CodeGen/AMDGPU/GlobalISel/regbankselect-amdgcn.interp.p1.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AMDGPU/GlobalISel/regbankselect-amdgcn.interp.p1.mir
@@ -0,0 +1,79 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -march=amdgcn -mcpu=fiji -run-pass=regbankselect -regbankselect-fast -verify-machineinstrs -o - %s | FileCheck %s
+# RUN: llc -march=amdgcn -mcpu=fiji -run-pass=regbankselect -regbankselect-greedy -verify-machineinstrs -o - %s | FileCheck %s
+
+---
+name: interp_p1_ss
+legalized: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0, $sgpr1
+    ; CHECK-LABEL: name: interp_p1_ss
+    ; CHECK: liveins: $sgpr0, $sgpr1
+    ; CHECK: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:sgpr(s32) = COPY $sgpr1
+    ; CHECK: [[COPY2:%[0-9]+]]:vgpr(s32) = COPY [[COPY]](s32)
+    ; CHECK: [[INT:%[0-9]+]]:vgpr(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p1), [[COPY2]](s32), 1, 1, [[COPY1]](s32)
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s32) = COPY $sgpr1
+    %2:_(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p1), %0, 1, 1, %1
+...
+
+---
+name: interp_p1_vs
+legalized: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $vgpr0, $sgpr0
+    ; CHECK-LABEL: name: interp_p1_vs
+    ; CHECK: liveins: $vgpr0, $sgpr0
+    ; CHECK: [[COPY:%[0-9]+]]:vgpr(s32) = COPY $vgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[INT:%[0-9]+]]:vgpr(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p1), [[COPY]](s32), 1, 1, [[COPY1]](s32)
+    %0:_(s32) = COPY $vgpr0
+    %1:_(s32) = COPY $sgpr0
+    %2:_(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p1), %0, 1, 1, %1
+...
+
+---
+name: interp_p1_sv
+legalized: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0, $vgpr0
+    ; CHECK-LABEL: name: interp_p1_sv
+    ; CHECK: liveins: $sgpr0, $vgpr0
+    ; CHECK: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:vgpr_32(s32) = COPY $vgpr0
+    ; CHECK: [[COPY2:%[0-9]+]]:vgpr(s32) = COPY [[COPY]](s32)
+    ; CHECK: [[V_READFIRSTLANE_B32_:%[0-9]+]]:sreg_32 = V_READFIRSTLANE_B32 [[COPY1]](s32), implicit $exec
+    ; CHECK: [[INT:%[0-9]+]]:vgpr(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p1), [[COPY2]](s32), 1, 1, [[V_READFIRSTLANE_B32_]]
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s32) = COPY $vgpr0
+    %2:_(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p1), %0, 1, 1, %1
+...
+
+---
+name: interp_p1_vv
+legalized: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $vgpr0, $vgpr1
+    ; CHECK-LABEL: name: interp_p1_vv
+    ; CHECK: liveins: $vgpr0, $vgpr1
+    ; CHECK: [[COPY:%[0-9]+]]:vgpr(s32) = COPY $vgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:vgpr_32(s32) = COPY $vgpr1
+    ; CHECK: [[V_READFIRSTLANE_B32_:%[0-9]+]]:sreg_32 = V_READFIRSTLANE_B32 [[COPY1]](s32), implicit $exec
+    ; CHECK: [[INT:%[0-9]+]]:vgpr(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p1), [[COPY]](s32), 1, 1, [[V_READFIRSTLANE_B32_]]
+    %0:_(s32) = COPY $vgpr0
+    %1:_(s32) = COPY $vgpr1
+    %2:_(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p1), %0, 1, 1, %1
+...
Index: llvm/test/CodeGen/AMDGPU/GlobalISel/regbankselect-amdgcn.interp.p2.f16.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AMDGPU/GlobalISel/regbankselect-amdgcn.interp.p2.f16.mir
@@ -0,0 +1,49 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -march=amdgcn -mcpu=fiji -run-pass=regbankselect %s -verify-machineinstrs -o - -regbankselect-fast | FileCheck %s
+# RUN: llc -march=amdgcn -mcpu=fiji -run-pass=regbankselect %s -verify-machineinstrs -o - -regbankselect-greedy | FileCheck %s
+
+---
+name: interp_p2_f16_sss
+legalized: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0, $sgpr1, $sgpr2
+
+    ; CHECK-LABEL: name: interp_p2_f16_sss
+    ; CHECK: liveins: $sgpr0, $sgpr1, $sgpr2
+    ; CHECK: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:sgpr(s32) = COPY $sgpr1
+    ; CHECK: [[COPY2:%[0-9]+]]:sgpr(s32) = COPY $sgpr2
+    ; CHECK: [[COPY3:%[0-9]+]]:vgpr(s32) = COPY [[COPY]](s32)
+    ; CHECK: [[COPY4:%[0-9]+]]:vgpr(s32) = COPY [[COPY1]](s32)
+    ; CHECK: [[INT:%[0-9]+]]:vgpr(s16) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p2.f16), [[COPY3]](s32), [[COPY4]](s32), 1, 1, 1, [[COPY2]](s32)
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s32) = COPY $sgpr1
+    %2:_(s32) = COPY $sgpr2
+    %3:_(s16) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p2.f16), %0, %1, 1, 1, 1, %2
+...
+
+---
+name: interp_p2_f16_ssv
+legalized: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0, $sgpr1, $vgpr0
+    ; CHECK-LABEL: name: interp_p2_f16_ssv
+    ; CHECK: liveins: $sgpr0, $sgpr1, $vgpr0
+    ; CHECK: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:sgpr(s32) = COPY $sgpr1
+    ; CHECK: [[COPY2:%[0-9]+]]:vgpr_32(s32) = COPY $vgpr0
+    ; CHECK: [[COPY3:%[0-9]+]]:vgpr(s32) = COPY [[COPY]](s32)
+    ; CHECK: [[COPY4:%[0-9]+]]:vgpr(s32) = COPY [[COPY1]](s32)
+    ; CHECK: [[V_READFIRSTLANE_B32_:%[0-9]+]]:sreg_32 = V_READFIRSTLANE_B32 [[COPY2]](s32), implicit $exec
+    ; CHECK: [[INT:%[0-9]+]]:vgpr(s16) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p2.f16), [[COPY3]](s32), [[COPY4]](s32), 1, 1, 1, [[V_READFIRSTLANE_B32_]]
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s32) = COPY $sgpr1
+    %2:_(s32) = COPY $vgpr0
+    %3:_(s16) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p2.f16), %0, %1, 1, 1, 1, %2
+...
Index: llvm/test/CodeGen/AMDGPU/GlobalISel/regbankselect-amdgcn.interp.p2.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AMDGPU/GlobalISel/regbankselect-amdgcn.interp.p2.mir
@@ -0,0 +1,48 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -march=amdgcn -mcpu=fiji -run-pass=regbankselect -regbankselect-fast -verify-machineinstrs -o - %s | FileCheck %s
+# RUN: llc -march=amdgcn -mcpu=fiji -run-pass=regbankselect -regbankselect-greedy -verify-machineinstrs -o - %s | FileCheck %s
+
+---
+name: interp_p2_sss
+legalized: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0, $sgpr1, $sgpr2
+    ; CHECK-LABEL: name: interp_p2_sss
+    ; CHECK: liveins: $sgpr0, $sgpr1, $sgpr2
+    ; CHECK: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:sgpr(s32) = COPY $sgpr1
+    ; CHECK: [[COPY2:%[0-9]+]]:sgpr(s32) = COPY $sgpr2
+    ; CHECK: [[COPY3:%[0-9]+]]:vgpr(s32) = COPY [[COPY]](s32)
+    ; CHECK: [[COPY4:%[0-9]+]]:vgpr(s32) = COPY [[COPY1]](s32)
+    ; CHECK: [[INT:%[0-9]+]]:vgpr(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p2), [[COPY3]](s32), [[COPY4]](s32), 1, 1, [[COPY2]](s32)
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s32) = COPY $sgpr1
+    %2:_(s32) = COPY $sgpr2
+    %3:_(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p2), %0, %1, 1, 1, %2
+...
+
+---
+name: interp_p2_ssv
+legalized: true
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0, $sgpr1, $vgpr0
+    ; CHECK-LABEL: name: interp_p2_ssv
+    ; CHECK: liveins: $sgpr0, $sgpr1, $vgpr0
+    ; CHECK: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:sgpr(s32) = COPY $sgpr1
+    ; CHECK: [[COPY2:%[0-9]+]]:vgpr_32(s32) = COPY $vgpr0
+    ; CHECK: [[COPY3:%[0-9]+]]:vgpr(s32) = COPY [[COPY]](s32)
+    ; CHECK: [[COPY4:%[0-9]+]]:vgpr(s32) = COPY [[COPY1]](s32)
+    ; CHECK: [[V_READFIRSTLANE_B32_:%[0-9]+]]:sreg_32 = V_READFIRSTLANE_B32 [[COPY2]](s32), implicit $exec
+    ; CHECK: [[INT:%[0-9]+]]:vgpr(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p2), [[COPY3]](s32), [[COPY4]](s32), 1, 1, [[V_READFIRSTLANE_B32_]]
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s32) = COPY $sgpr1
+    %2:_(s32) = COPY  $vgpr0
+    %3:_(s32) = G_INTRINSIC intrinsic(@llvm.amdgcn.interp.p2), %0, %1, 1, 1, %2
+...