AMDGPU/GlobalISel: Add new utils file

There are some things that are shareable between the legalizer,
regbankselect, and the selector that don't have an obvious place to
go.

llvm/lib/Target/AMDGPU/AMDGPUGlobalISelUtils.cpp

@@ -0,0 +1,45 @@
+//===- AMDGPUGlobalISelUtils.cpp ---------------------------------*- C++ -*-==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "AMDGPUGlobalISelUtils.h"
+#include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
+#include "llvm/IR/Constants.h"
+
+using namespace llvm;
+using namespace MIPatternMatch;
+
+std::tuple<Register, unsigned, MachineInstr *>
+AMDGPU::getBaseWithConstantOffset(MachineRegisterInfo &MRI, Register Reg) {
+  MachineInstr *Def = getDefIgnoringCopies(Reg, MRI);
+  if (!Def)
+    return std::make_tuple(Reg, 0, nullptr);
+
+  if (Def->getOpcode() == TargetOpcode::G_CONSTANT) {
+    unsigned Offset;
+    const MachineOperand &Op = Def->getOperand(1);
+    if (Op.isImm())
+      Offset = Op.getImm();
+    else
+      Offset = Op.getCImm()->getZExtValue();
+
+    return std::make_tuple(Register(), Offset, Def);
+  }
+
+  int64_t Offset;
+  if (Def->getOpcode() == TargetOpcode::G_ADD) {
+    // TODO: Handle G_OR used for add case
+    if (mi_match(Def->getOperand(2).getReg(), MRI, m_ICst(Offset)))
+      return std::make_tuple(Def->getOperand(1).getReg(), Offset, Def);
+
+    // FIXME: matcher should ignore copies
+    if (mi_match(Def->getOperand(2).getReg(), MRI, m_Copy(m_ICst(Offset))))
+      return std::make_tuple(Def->getOperand(1).getReg(), Offset, Def);
+  }
+
+  return std::make_tuple(Reg, 0, Def);
+}

llvm/lib/Target/AMDGPU/AMDGPUGlobalISelUtils.h

@@ -0,0 +1,29 @@
+//===- AMDGPUGlobalISelUtils -------------------------------------*- C++ -*-==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_AMDGPU_AMDGPUGLOBALISELUTILS_H
+#define LLVM_LIB_TARGET_AMDGPU_AMDGPUGLOBALISELUTILS_H
+
+#include "llvm/CodeGen/Register.h"
+#include <tuple>
+
+namespace llvm {
+
+class MachineInstr;
+class MachineRegisterInfo;
+
+namespace AMDGPU {
+
+/// Returns Base register, constant offset, and offset def point.
+std::tuple<Register, unsigned, MachineInstr *>
+getBaseWithConstantOffset(MachineRegisterInfo &MRI, Register Reg);
+
+}
+}
+
+#endif

llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp

@@ -13,6 +13,7 @@
 
 #include "AMDGPUInstructionSelector.h"
 #include "AMDGPUInstrInfo.h"
+#include "AMDGPUGlobalISelUtils.h"
 #include "AMDGPURegisterBankInfo.h"
 #include "AMDGPURegisterInfo.h"
 #include "AMDGPUSubtarget.h"
@@ -801,38 +802,6 @@ static unsigned extractSWZ(unsigned AuxiliaryData) {
   return (AuxiliaryData >> 3) & 1;
 }
 
-// Returns Base register, constant offset, and offset def point.
-static std::tuple<Register, unsigned, MachineInstr *>
-getBaseWithConstantOffset(MachineRegisterInfo &MRI, Register Reg) {
-  MachineInstr *Def = getDefIgnoringCopies(Reg, MRI);
-  if (!Def)
-    return std::make_tuple(Reg, 0, nullptr);
-
-  if (Def->getOpcode() == AMDGPU::G_CONSTANT) {
-    unsigned Offset;
-    const MachineOperand &Op = Def->getOperand(1);
-    if (Op.isImm())
-      Offset = Op.getImm();
-    else
-      Offset = Op.getCImm()->getZExtValue();
-
-    return std::make_tuple(Register(), Offset, Def);
-  }
-
-  int64_t Offset;
-  if (Def->getOpcode() == AMDGPU::G_ADD) {
-    // TODO: Handle G_OR used for add case
-    if (mi_match(Def->getOperand(2).getReg(), MRI, m_ICst(Offset)))
-      return std::make_tuple(Def->getOperand(1).getReg(), Offset, Def);
-
-    // FIXME: matcher should ignore copies
-    if (mi_match(Def->getOperand(2).getReg(), MRI, m_Copy(m_ICst(Offset))))
-      return std::make_tuple(Def->getOperand(1).getReg(), Offset, Def);
-  }
-
-  return std::make_tuple(Reg, 0, Def);
-}
-
 static unsigned getBufferStoreOpcode(LLT Ty,
                                      const unsigned MemSize,
                                      const bool Offen) {
@@ -929,7 +898,7 @@ AMDGPUInstructionSelector::splitBufferOffsets(MachineIRBuilder &B,
   MachineInstr *OffsetDef;
 
   std::tie(BaseReg, TotalConstOffset, OffsetDef)
-    = getBaseWithConstantOffset(*MRI, OrigOffset);
+    = AMDGPU::getBaseWithConstantOffset(*MRI, OrigOffset);
 
   unsigned ImmOffset = TotalConstOffset;
 

llvm/lib/Target/AMDGPU/CMakeLists.txt

@@ -45,6 +45,7 @@ add_llvm_target(AMDGPUCodeGen
   AMDGPUInstructionSelector.cpp
   AMDGPUISelDAGToDAG.cpp
   AMDGPUISelLowering.cpp
+  AMDGPUGlobalISelUtils.cpp
   AMDGPULegalizerInfo.cpp
   AMDGPULibCalls.cpp
   AMDGPULibFunc.cpp