Index: llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
===================================================================
--- llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
+++ llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
@@ -34,6 +34,8 @@
 Align GISelKnownBits::computeKnownAlignment(Register R, unsigned Depth) {
   const MachineInstr *MI = MRI.getVRegDef(R);
   switch (MI->getOpcode()) {
+  case TargetOpcode::COPY:
+    return computeKnownAlignment(MI->getOperand(1).getReg(), Depth);
   case TargetOpcode::G_FRAME_INDEX: {
     int FrameIdx = MI->getOperand(1).getIndex();
     return MF.getFrameInfo().getObjectAlign(FrameIdx);
Index: llvm/lib/Target/AMDGPU/SIISelLowering.h
===================================================================
--- llvm/lib/Target/AMDGPU/SIISelLowering.h
+++ llvm/lib/Target/AMDGPU/SIISelLowering.h
@@ -402,6 +402,9 @@
                                      KnownBits &Known,
                                      const MachineFunction &MF) const override;
 
+  Align computeKnownAlignForTargetInstr(GISelKnownBits &Analysis, Register R,
+                                        const MachineRegisterInfo &MRI,
+                                        unsigned Depth = 0) const override;
   bool isSDNodeSourceOfDivergence(const SDNode *N,
     FunctionLoweringInfo *FLI, LegacyDivergenceAnalysis *DA) const override;
 
Index: llvm/lib/Target/AMDGPU/SIISelLowering.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -11163,6 +11163,30 @@
   Known.Zero.setHighBits(getSubtarget()->getKnownHighZeroBitsForFrameIndex());
 }
 
+Align SITargetLowering::computeKnownAlignForTargetInstr(
+  GISelKnownBits &KB, Register R, const MachineRegisterInfo &MRI,
+  unsigned Depth) const {
+  const MachineInstr *MI = MRI.getVRegDef(R);
+  switch (MI->getOpcode()) {
+  case AMDGPU::G_INTRINSIC: {
+    switch (MI->getIntrinsicID()) {
+    case Intrinsic::amdgcn_dispatch_ptr:
+    case Intrinsic::amdgcn_queue_ptr:
+    case Intrinsic::amdgcn_kernarg_segment_ptr:
+    case Intrinsic::amdgcn_implicitarg_ptr:
+    case Intrinsic::amdgcn_implicit_buffer_ptr:
+      // FIXME: Is there a way to get the default alignment from the intrinsic
+      // declaration?
+      return Align(4);
+    default:
+      return Align(1);
+    }
+  }
+  default:
+    return Align(1);
+  }
+}
+
 Align SITargetLowering::getPrefLoopAlignment(MachineLoop *ML) const {
   const Align PrefAlign = TargetLowering::getPrefLoopAlignment(ML);
   const Align CacheLineAlign = Align(64);
Index: llvm/unittests/CodeGen/GlobalISel/KnownBitsTest.cpp
===================================================================
--- llvm/unittests/CodeGen/GlobalISel/KnownBitsTest.cpp
+++ llvm/unittests/CodeGen/GlobalISel/KnownBitsTest.cpp
@@ -431,3 +431,35 @@
   EXPECT_EQ(16u, Info.computeNumSignBits(CopyLoadUShort));
   EXPECT_EQ(17u, Info.computeNumSignBits(CopyLoadSShort));
 }
+
+TEST_F(AMDGPUGISelMITest, TestTargetKnownAlign) {
+  StringRef MIRString =
+    "  %5:_(p4) = G_INTRINSIC intrinsic(@llvm.amdgcn.dispatch.ptr)\n"
+    "  %6:_(p4) = COPY %5\n"
+    "  %7:_(p4) = G_INTRINSIC intrinsic(@llvm.amdgcn.queue.ptr)\n"
+    "  %8:_(p4) = COPY %7\n"
+    "  %9:_(p4) = G_INTRINSIC intrinsic(@llvm.amdgcn.kernarg.segment.ptr)\n"
+    "  %10:_(p4) = COPY %9\n"
+    "  %11:_(p4) = G_INTRINSIC intrinsic(@llvm.amdgcn.implicitarg.ptr)\n"
+    "  %12:_(p4) = COPY %11\n"
+    "  %13:_(p4) = G_INTRINSIC intrinsic(@llvm.amdgcn.implicit.buffer.ptr)\n"
+    "  %14:_(p4) = COPY %13\n";
+
+  setUp(MIRString);
+  if (!TM)
+    return;
+
+  Register CopyDispatchPtr = Copies[Copies.size() - 5];
+  Register CopyQueuePtr = Copies[Copies.size() - 4];
+  Register CopyKernargSegmentPtr = Copies[Copies.size() - 3];
+  Register CopyImplicitArgPtr = Copies[Copies.size() - 2];
+  Register CopyImplicitBufferPtr = Copies[Copies.size() - 1];
+
+  GISelKnownBits Info(*MF);
+
+  EXPECT_EQ(Align(4), Info.computeKnownAlignment(CopyDispatchPtr));
+  EXPECT_EQ(Align(4), Info.computeKnownAlignment(CopyQueuePtr));
+  EXPECT_EQ(Align(4), Info.computeKnownAlignment(CopyKernargSegmentPtr));
+  EXPECT_EQ(Align(4), Info.computeKnownAlignment(CopyImplicitArgPtr));
+  EXPECT_EQ(Align(4), Info.computeKnownAlignment(CopyImplicitBufferPtr));
+}