ARM: Add a postRA pass to legalize stack offsets. Greedy approach (reserve IP).

src/IceTargetLoweringX86BaseImpl.h

Index: src/IceTargetLoweringX86BaseImpl.h
diff --git a/src/IceTargetLoweringX86BaseImpl.h b/src/IceTargetLoweringX86BaseImpl.h
index 77048b089c1a4c9934568f8dd973429138e36f9c..5ce22ba661afec10777095748a172d1b3ca5e9c7 100644
--- a/src/IceTargetLoweringX86BaseImpl.h
+++ b/src/IceTargetLoweringX86BaseImpl.h
@@ -747,6 +747,8 @@ IceString TargetX86Base<Machine>::getRegName(SizeT RegNum, Type Ty) const {
 
 template <class Machine>
 void TargetX86Base<Machine>::emitVariable(const Variable *Var) const {
+  if (!BuildDefs::dump())
+    return;
   Ostream &Str = Ctx->getStrEmit();
   if (Var->hasReg()) {
     Str << "%" << getRegName(Var->getRegNum(), Var->getType());
@@ -756,12 +758,16 @@ void TargetX86Base<Machine>::emitVariable(const Variable *Var) const {
     llvm_unreachable("Infinite-weight Variable has no register assigned");
   }
   int32_t Offset = Var->getStackOffset();
-  if (!hasFramePointer())
-    Offset += getStackAdjustment();
+  int32_t BaseRegNum = Var->getBaseRegNum();
+  if (BaseRegNum == Variable::NoRegister) {
+    BaseRegNum = getFrameOrStackReg();
+    if (!hasFramePointer())
+      Offset += getStackAdjustment();
+  }
   if (Offset)
     Str << Offset;
   const Type FrameSPTy = IceType_i32;
-  Str << "(%" << getRegName(getFrameOrStackReg(), FrameSPTy) << ")";
+  Str << "(%" << getRegName(BaseRegNum, FrameSPTy) << ")";
 }
 
 template <class Machine>
@@ -773,10 +779,14 @@ TargetX86Base<Machine>::stackVarToAsmOperand(const Variable *Var) const {
     llvm_unreachable("Infinite-weight Variable has no register assigned");
   }
   int32_t Offset = Var->getStackOffset();
-  if (!hasFramePointer())
-    Offset += getStackAdjustment();
+  int32_t BaseRegNum = Var->getBaseRegNum();
+  if (Var->getBaseRegNum() == Variable::NoRegister) {
+    BaseRegNum = getFrameOrStackReg();
+    if (!hasFramePointer())
+      Offset += getStackAdjustment();
+  }
   return typename Traits::Address(
-      Traits::RegisterSet::getEncodedGPR(getFrameOrStackReg()), Offset);
+      Traits::RegisterSet::getEncodedGPR(BaseRegNum), Offset);
 }
 
 template <class Machine> void TargetX86Base<Machine>::lowerArguments() {