[lanai] Add areMemAccessesTriviallyDisjoint, getMemOpBaseRegImmOfs and getMemOpBaseRegImmOfsWidth.

[jpienaar]

Summary

Add getMemOpBaseRegImmOfsWidth to enable determining independence during MiSched.

[mcrosier]

You're going to need lots of tests... :)

[jpienaar]

Adding simple test case to verify effect on scheduling DAG due to areMemAccessesTriviallyDisjoint change.

[jpienaar]

@mcrosier: Yes indeed, funny things can happen if these are wrong :). Added a IR test to test some of the different code paths in areMemAccessesTriviallyDisjoint.

[jpienaar]

Friendly ping

[majnemer]

lib/Target/Lanai/LanaiInstrInfo.cpp

110

std::min?

111

std::max?

113

Please clang-format this.

362

clang-format this

368–387

clang-format this too.

397–411

And this.

411

Extra semicolon.

test/CodeGen/Lanai/lanai-misched-trivial-disjoint.ll

1 ↗

(On Diff #53188)

I'd recommend piping the file in via stdin:

llc < %s -mtriple=lanai-unknown-unknown -debug-only=misched -o /dev/null 2>&1

This prevents the path to the file from showing up in any of LLVM's output. Occasionally, this causes problems if content that a CHECK line is searching for can be found inside of a path.

6 ↗

(On Diff #53188)

I'd remove this comment

[jpienaar]

Updated to address comments.

[jpienaar]

Updated, thanks

test/CodeGen/Lanai/lanai-misched-trivial-disjoint.ll

1 ↗

(On Diff #53188)

Fixed thanks. Didn't think about check matching on the path.

[majnemer]

LGTM

lib/Target/Lanai/LanaiInstrInfo.h

public:
 
   // getRegisterInfo - TargetInstrInfo is a superset of MRegister info.  As
   // such, whenever a client has an instance of instruction info, it should
   // always be able to get register info as well (through this method).
   virtual const LanaiRegisterInfo &getRegisterInfo() const {
     return RegisterInfo;
   }
 
+  bool areMemAccessesTriviallyDisjoint(MachineInstr *MIa, MachineInstr *MIb,
+                                       AliasAnalysis *AA) const override;
+
   unsigned isLoadFromStackSlot(const MachineInstr *MI,
                                int &FrameIndex) const override;
 
   unsigned isLoadFromStackSlotPostFE(const MachineInstr *MI,
                                      int &FrameIndex) const override;
 
   unsigned isStoreToStackSlot(const MachineInstr *MI,
                               int &FrameIndex) const override;
public:
   loadRegFromStackSlot(MachineBasicBlock &MBB,
                        MachineBasicBlock::iterator Position,
                        unsigned DestinationRegister, int FrameIndex,
                        const TargetRegisterClass *RegisterClass,
                        const TargetRegisterInfo *RegisterInfo) const override;
 
   bool expandPostRAPseudo(MachineBasicBlock::iterator MI) const override;
 
+  bool getMemOpBaseRegImmOfs(MachineInstr *LdSt, unsigned &BaseReg,
+                             int64_t &Offset,
+                             const TargetRegisterInfo *TRI) const override;
+
+  bool getMemOpBaseRegImmOfsWidth(MachineInstr *LdSt, unsigned &BaseReg,
+                                  int64_t &Offset, unsigned &Width,
+                                  const TargetRegisterInfo *TRI) const;
+
   bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TrueBlock,
                      MachineBasicBlock *&FalseBlock,
                      SmallVectorImpl<MachineOperand> &Condition,
                      bool AllowModify) const override;
 
   unsigned RemoveBranch(MachineBasicBlock &MBB) const override;
 
   bool ReverseBranchCondition(

lib/Target/Lanai/LanaiInstrInfo.cpp

 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/TargetRegistry.h"
 
+using namespace llvm;
+
 #define GET_INSTRINFO_CTOR_DTOR
 #include "LanaiGenInstrInfo.inc"
 
-namespace llvm {
 LanaiInstrInfo::LanaiInstrInfo()
     : LanaiGenInstrInfo(Lanai::ADJCALLSTACKDOWN, Lanai::ADJCALLSTACKUP),
       RegisterInfo() {}
 
 void LanaiInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
                                  MachineBasicBlock::iterator Position,
                                  DebugLoc DL, unsigned DestinationRegister,
                                  unsigned SourceRegister,
if (!Lanai::GPRRegClass.hasSubClassEq(RegisterClass)) {
     llvm_unreachable("Can't load this register from stack slot");
   }
   BuildMI(MBB, Position, DL, get(Lanai::LDW_RI), DestinationRegister)
       .addFrameIndex(FrameIndex)
       .addImm(0)
       .addImm(LPAC::ADD);
 }
 
+bool LanaiInstrInfo::areMemAccessesTriviallyDisjoint(MachineInstr *MIa,
+                                                     MachineInstr *MIb,
+                                                     AliasAnalysis *AA) const {
+  assert(MIa && MIa->mayLoadOrStore() && "MIa must be a load or store.");
+  assert(MIb && MIb->mayLoadOrStore() && "MIb must be a load or store.");
+
+  if (MIa->hasUnmodeledSideEffects() || MIb->hasUnmodeledSideEffects() ||
+      MIa->hasOrderedMemoryRef() || MIb->hasOrderedMemoryRef())
+    return false;
+
+  // Retrieve the base register, offset from the base register and width. Width
+  // is the size of memory that is being loaded/stored (e.g. 1, 2, 4).  If
+  // base registers are identical, and the offset of a lower memory access +
+  // 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;
+  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) {
+      int LowOffset = OffsetA < OffsetB ? OffsetA : OffsetB;
+      int HighOffset = OffsetA < OffsetB ? OffsetB : OffsetA;
+      int LowWidth = (LowOffset == OffsetA) ? WidthA : WidthB;
+      if (LowOffset + LowWidth <= HighOffset) return true;
+    }
+  }
+  return false;
+}
+
 bool LanaiInstrInfo::expandPostRAPseudo(MachineBasicBlock::iterator MI) const {
   return false;
 }
 
 static LPCC::CondCode GetOppositeBranchCondition(LPCC::CondCode CC) {
   switch (CC) {
   case LPCC::ICC_T: //  true
     return LPCC::ICC_F;
unsigned LanaiInstrInfo::isStoreToStackSlot(const MachineInstr *MI,
   if (MI->getOpcode() == Lanai::SW_RI)
     if (MI->getOperand(0).isFI() && MI->getOperand(1).isImm() &&
         MI->getOperand(1).getImm() == 0) {
       FrameIndex = MI->getOperand(0).getIndex();
       return MI->getOperand(2).getReg();
     }
   return 0;
 }
-} // namespace llvm
+
+bool LanaiInstrInfo::getMemOpBaseRegImmOfsWidth(
+    MachineInstr *LdSt, unsigned &BaseReg, 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) return false;
+  if (!LdSt->getOperand(1).isReg() || !LdSt->getOperand(2).isImm() ||
+      !(LdSt->getOperand(3).isImm() &&
+        LdSt->getOperand(3).getImm() == LPAC::ADD))
+    return false;
+
+  switch (LdSt->getOpcode()) {
+    default:
+      return false;
+    case Lanai::LDW_RI:
+    case Lanai::LDW_RR:
+    case Lanai::SW_RR:
+    case Lanai::SW_RI:
+      Width = 4;
+      break;
+    case Lanai::LDHs_RI:
+    case Lanai::LDHz_RI:
+    case Lanai::STH_RI:
+      Width = 2;
+      break;
+    case Lanai::LDBs_RI:
+    case Lanai::LDBz_RI:
+    case Lanai::STB_RI:
+      Width = 1;
+      break;
+  }
+
+  BaseReg = LdSt->getOperand(1).getReg();
+  Offset = LdSt->getOperand(2).getImm();
+  return true;
+}
+
+bool LanaiInstrInfo::getMemOpBaseRegImmOfs(
+    MachineInstr *LdSt, unsigned &BaseReg, int64_t &Offset,
+    const TargetRegisterInfo *TRI) const {
+  switch (LdSt->getOpcode()) {
+    default:
+      return false;
+    case Lanai::LDW_RI:
+    case Lanai::LDW_RR:
+    case Lanai::SW_RR:
+    case Lanai::SW_RI:
+    case Lanai::LDHs_RI:
+    case Lanai::LDHz_RI:
+    case Lanai::STH_RI:
+    case Lanai::LDBs_RI:
+    case Lanai::LDBz_RI:
+      unsigned Width;
+      return getMemOpBaseRegImmOfsWidth(LdSt, BaseReg, Offset, Width, TRI);
+  };
+}