[turbofan] Add backend support for signed loads.

src/compiler/arm/instruction-selector-arm.cc

Index: src/compiler/arm/instruction-selector-arm.cc
diff --git a/src/compiler/arm/instruction-selector-arm.cc b/src/compiler/arm/instruction-selector-arm.cc
index 90c8eb530039a5a65c6453ce1f114baddfe5bf10..6ec86bd6413d9c3e3ff04b6d5877e97218f4a0f3 100644
--- a/src/compiler/arm/instruction-selector-arm.cc
+++ b/src/compiler/arm/instruction-selector-arm.cc
@@ -55,19 +55,21 @@ class ArmOperandGenerator V8_FINAL : public OperandGenerator {
       case kArmRsb:
         return ImmediateFitsAddrMode1Instruction(value);
 
-      case kArmFloat64Load:
-      case kArmFloat64Store:
+      case kArmVldr64:
+      case kArmVstr64:
         return value >= -1020 && value <= 1020 && (value % 4) == 0;
 
-      case kArmLoadWord8:
-      case kArmStoreWord8:
-      case kArmLoadWord32:
-      case kArmStoreWord32:
+      case kArmLdrb:
+      case kArmLdrsb:
+      case kArmStrb:
+      case kArmLdr:
+      case kArmStr:
       case kArmStoreWriteBarrier:
         return value >= -4095 && value <= 4095;
 
-      case kArmLoadWord16:
-      case kArmStoreWord16:
+      case kArmLdrh:
+      case kArmLdrsh:
+      case kArmStrh:
         return value >= -255 && value <= 255;
 
       case kArchJmp:
@@ -287,6 +289,7 @@ static void VisitBinop(InstructionSelector* selector, Node* node,
 
 void InstructionSelector::VisitLoad(Node* node) {
   MachineType rep = RepresentationOf(OpParameter<MachineType>(node));
+  MachineType typ = TypeOf(OpParameter<MachineType>(node));
   ArmOperandGenerator g(this);
   Node* base = node->InputAt(0);
   Node* index = node->InputAt(1);
@@ -296,21 +299,20 @@ void InstructionSelector::VisitLoad(Node* node) {
                                    : g.DefineAsRegister(node);
 
   ArchOpcode opcode;
-  // TODO(titzer): signed/unsigned small loads
   switch (rep) {
     case kRepFloat64:
-      opcode = kArmFloat64Load;
+      opcode = kArmVldr64;
       break;
     case kRepBit:  // Fall through.
     case kRepWord8:
-      opcode = kArmLoadWord8;
+      opcode = typ == kTypeUint32 ? kArmLdrb : kArmLdrsb;
       break;
     case kRepWord16:
-      opcode = kArmLoadWord16;
+      opcode = typ == kTypeUint32 ? kArmLdrh : kArmLdrsh;
       break;
     case kRepTagged:  // Fall through.
     case kRepWord32:
-      opcode = kArmLoadWord32;
+      opcode = kArmLdr;
       break;
     default:
       UNREACHABLE();
@@ -320,9 +322,6 @@ void InstructionSelector::VisitLoad(Node* node) {
   if (g.CanBeImmediate(index, opcode)) {
     Emit(opcode | AddressingModeField::encode(kMode_Offset_RI), result,
          g.UseRegister(base), g.UseImmediate(index));
-  } else if (g.CanBeImmediate(base, opcode)) {
-    Emit(opcode | AddressingModeField::encode(kMode_Offset_RI), result,
-         g.UseRegister(index), g.UseImmediate(base));
   } else {
     Emit(opcode | AddressingModeField::encode(kMode_Offset_RR), result,
          g.UseRegister(base), g.UseRegister(index));
@@ -356,18 +355,18 @@ void InstructionSelector::VisitStore(Node* node) {
   ArchOpcode opcode;
   switch (rep) {
     case kRepFloat64:
-      opcode = kArmFloat64Store;
+      opcode = kArmVstr64;
       break;
     case kRepBit:  // Fall through.
     case kRepWord8:
-      opcode = kArmStoreWord8;
+      opcode = kArmStrb;
       break;
     case kRepWord16:
-      opcode = kArmStoreWord16;
+      opcode = kArmStrh;
       break;
     case kRepTagged:  // Fall through.
     case kRepWord32:
-      opcode = kArmStoreWord32;
+      opcode = kArmStr;
       break;
     default:
       UNREACHABLE();
@@ -377,9 +376,6 @@ void InstructionSelector::VisitStore(Node* node) {
   if (g.CanBeImmediate(index, opcode)) {
     Emit(opcode | AddressingModeField::encode(kMode_Offset_RI), NULL,
          g.UseRegister(base), g.UseImmediate(index), val);
-  } else if (g.CanBeImmediate(base, opcode)) {
-    Emit(opcode | AddressingModeField::encode(kMode_Offset_RI), NULL,
-         g.UseRegister(index), g.UseImmediate(base), val);
   } else {
     Emit(opcode | AddressingModeField::encode(kMode_Offset_RR), NULL,
          g.UseRegister(base), g.UseRegister(index), val);