Subzero: Transform suitable Load/Arith/Store sequences into RMW ops.

src/IceInst.cpp

 //===- subzero/src/IceInst.cpp - High-level instruction implementation ----===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the Inst class, primarily the various
@@ skipping 404 matching lines @@
 InstSelect::InstSelect(Cfg *Func, Variable *Dest, Operand *Condition,
                        Operand *SourceTrue, Operand *SourceFalse)
     : InstHighLevel(Func, Inst::Select, 3, Dest) {
   assert(typeElementType(Condition->getType()) == IceType_i1);
   addSource(Condition);
   addSource(SourceTrue);
   addSource(SourceFalse);
 }
 
 InstStore::InstStore(Cfg *Func, Operand *Data, Operand *Addr)
-    : InstHighLevel(Func, Inst::Store, 2, nullptr) {
+    : InstHighLevel(Func, Inst::Store, 3, nullptr) {
   addSource(Data);
   addSource(Addr);
+  // The 3rd operand is a dummy placeholder for the RMW beacon.
+  addSource(Data);
+}
+
+void InstStore::setRmwBeacon(Variable *Beacon) {
+  Dest = llvm::dyn_cast<Variable>(getData());
+  Srcs[2] = Beacon;
 }
 
 InstSwitch::InstSwitch(Cfg *Func, SizeT NumCases, Operand *Source,
                        CfgNode *LabelDefault)
     : InstHighLevel(Func, Inst::Switch, 1, nullptr), LabelDefault(LabelDefault),
       NumCases(NumCases) {
   addSource(Source);
   Values = Func->allocateArrayOf<uint64_t>(NumCases);
   Labels = Func->allocateArrayOf<CfgNode *>(NumCases);
   // Initialize in case buggy code doesn't set all entries
@@ skipping 302 matching lines @@
   Str << " = load " << Ty << ", " << Ty << "* ";
   dumpSources(Func);
   Str << ", align " << typeAlignInBytes(Ty);
 }
 
 void InstStore::dump(const Cfg *Func) const {
   if (!ALLOW_DUMP)
     return;
   Ostream &Str = Func->getContext()->getStrDump();
   Type Ty = getData()->getType();
+  dumpDest(Func);
+  if (Dest)
+    Str << " = ";
   Str << "store " << Ty << " ";
   getData()->dump(Func);
   Str << ", " << Ty << "* ";
   getAddr()->dump(Func);
   Str << ", align " << typeAlignInBytes(Ty);
+  if (getRmwBeacon()) {
+    Str << ", beacon ";
+    getRmwBeacon()->dump(Func);
+  }
 }
 
 void InstSwitch::dump(const Cfg *Func) const {
   if (!ALLOW_DUMP)
     return;
   Ostream &Str = Func->getContext()->getStrDump();
   Type Ty = getComparison()->getType();
   Str << "switch " << Ty << " ";
   getSrc(0)->dump(Func);
   Str << ", label %" << getLabelDefault()->getName() << " [\n";
@@ skipping 156 matching lines @@
     // preserve these.
     return true;
   }
   if (!Dest->hasReg() && !SrcVar->hasReg() &&
       Dest->getStackOffset() == SrcVar->getStackOffset())
     return true;
   return false;
 }
 
 } // end of namespace Ice