[CodeGen][NFC] Make `TII::getMemOpBaseImmOfs` return a base operand

Currently, instructions doing memory accesses through a base operand that is
not a register can not be analyzed using `TII::getMemOpBaseRegImmOfs`.

This means that functions such as `TII::shouldClusterMemOps` will bail
out on instructions using an FI as a base instead of a register.

The goal of this patch is to refactor all this to return a base
operand instead of a base register.

Then in a separate patch, I will add FI support to the mem op clustering
in the MachineScheduler.

Differential Revision: https://reviews.llvm.org/D54846

2 files changed, 21 insertions, 18 deletions

diff --git a/llvm/lib/Target/Lanai/LanaiInstrInfo.cpp b/llvm/lib/Target/Lanai/LanaiInstrInfo.cpp
index a18352738e1..196768fdc56 100644
--- a/llvm/lib/Target/Lanai/LanaiInstrInfo.cpp
+++ b/llvm/lib/Target/Lanai/LanaiInstrInfo.cpp
@@ -101,12 +101,12 @@ bool LanaiInstrInfo::areMemAccessesTriviallyDisjoint(
   // the width doesn't overlap the offset of a higher memory access,
   // then the memory accesses are different.
   const TargetRegisterInfo *TRI = &getRegisterInfo();
-  unsigned BaseRegA = 0, BaseRegB = 0;
+  MachineOperand *BaseOpA = nullptr, *BaseOpB = nullptr;
   int64_t OffsetA = 0, OffsetB = 0;
   unsigned int WidthA = 0, WidthB = 0;
-  if (getMemOpBaseRegImmOfsWidth(MIa, BaseRegA, OffsetA, WidthA, TRI) &&
-      getMemOpBaseRegImmOfsWidth(MIb, BaseRegB, OffsetB, WidthB, TRI)) {
-    if (BaseRegA == BaseRegB) {
+  if (getMemOperandWithOffsetWidth(MIa, BaseOpA, OffsetA, WidthA, TRI) &&
+      getMemOperandWithOffsetWidth(MIb, BaseOpB, OffsetB, WidthB, TRI)) {
+    if (BaseOpA->isIdenticalTo(*BaseOpB)) {
       int LowOffset = std::min(OffsetA, OffsetB);
       int HighOffset = std::max(OffsetA, OffsetB);
       int LowWidth = (LowOffset == OffsetA) ? WidthA : WidthB;
@@ -755,9 +755,9 @@ unsigned LanaiInstrInfo::isStoreToStackSlot(const MachineInstr &MI,
   return 0;
 }
 
-bool LanaiInstrInfo::getMemOpBaseRegImmOfsWidth(
-    MachineInstr &LdSt, unsigned &BaseReg, int64_t &Offset, unsigned &Width,
-    const TargetRegisterInfo * /*TRI*/) const {
+bool LanaiInstrInfo::getMemOperandWithOffsetWidth(
+    MachineInstr &LdSt, MachineOperand *&BaseOp, int64_t &Offset,
+    unsigned &Width, const TargetRegisterInfo * /*TRI*/) const {
   // Handle only loads/stores with base register followed by immediate offset
   // and with add as ALU op.
   if (LdSt.getNumOperands() != 4)
@@ -787,14 +787,17 @@ bool LanaiInstrInfo::getMemOpBaseRegImmOfsWidth(
     break;
   }
 
-  BaseReg = LdSt.getOperand(1).getReg();
+  BaseOp = &LdSt.getOperand(1);
   Offset = LdSt.getOperand(2).getImm();
+  assert(BaseOp->isReg() && "getMemOperandWithOffset only supports base "
+                            "operands of type register.");
   return true;
 }
 
-bool LanaiInstrInfo::getMemOpBaseRegImmOfs(
-    MachineInstr &LdSt, unsigned &BaseReg, int64_t &Offset,
-    const TargetRegisterInfo *TRI) const {
+bool LanaiInstrInfo::getMemOperandWithOffset(MachineInstr &LdSt,
+                                        MachineOperand *&BaseOp,
+                                        int64_t &Offset,
+                                        const TargetRegisterInfo *TRI) const {
   switch (LdSt.getOpcode()) {
   default:
     return false;
@@ -808,6 +811,6 @@ bool LanaiInstrInfo::getMemOpBaseRegImmOfs(
   case Lanai::LDBs_RI:
   case Lanai::LDBz_RI:
     unsigned Width;
-    return getMemOpBaseRegImmOfsWidth(LdSt, BaseReg, Offset, Width, TRI);
+    return getMemOperandWithOffsetWidth(LdSt, BaseOp, Offset, Width, TRI);
   }
 }
diff --git a/llvm/lib/Target/Lanai/LanaiInstrInfo.h b/llvm/lib/Target/Lanai/LanaiInstrInfo.h
index fe22fde2470..bdcf9a361b5 100644
--- a/llvm/lib/Target/Lanai/LanaiInstrInfo.h
+++ b/llvm/lib/Target/Lanai/LanaiInstrInfo.h
@@ -68,13 +68,13 @@ public:
 
   bool expandPostRAPseudo(MachineInstr &MI) const override;
 
-  bool getMemOpBaseRegImmOfs(MachineInstr &LdSt, unsigned &BaseReg,
-                             int64_t &Offset,
-                             const TargetRegisterInfo *TRI) const override;
+  bool getMemOperandWithOffset(MachineInstr &LdSt, MachineOperand *&BaseOp,
+                               int64_t &Offset,
+                               const TargetRegisterInfo *TRI) const override;
 
-  bool getMemOpBaseRegImmOfsWidth(MachineInstr &LdSt, unsigned &BaseReg,
-                                  int64_t &Offset, unsigned &Width,
-                                  const TargetRegisterInfo *TRI) const;
+  bool getMemOperandWithOffsetWidth(MachineInstr &LdSt, MachineOperand *&BaseOp,
+                                    int64_t &Offset, unsigned &Width,
+                                    const TargetRegisterInfo *TRI) const;
 
   std::pair<unsigned, unsigned>
   decomposeMachineOperandsTargetFlags(unsigned TF) const override;