Subzero ARM: lowerArguments (GPR), basic legalize(), and lowerRet(i32, i64).

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 855 matching lines @@
 }
 
 void InstTarget::dump(const Cfg *Func) const {
   if (!ALLOW_DUMP)
     return;
   Ostream &Str = Func->getContext()->getStrDump();
   Str << "[TARGET] ";
   Inst::dump(Func);
 }
 
+bool checkForRedundantAssign(const Variable *Dest, const Operand *Source) {
+  const auto SrcVar = llvm::dyn_cast<const Variable>(Source);
+  if (!SrcVar)
+    return false;
+  if (Dest->hasReg() && Dest->getRegNum() == SrcVar->getRegNum()) {
+    // TODO: On x86-64, instructions like "mov eax, eax" are used to
+    // clear the upper 32 bits of rax.  We need to recognize and
+    // preserve these.
+    return true;
+  }
+  if (!Dest->hasReg() && !SrcVar->hasReg() &&
+      Dest->getStackOffset() == SrcVar->getStackOffset())
+    return true;
+  return false;
+}
+
 } // end of namespace Ice