[turbofan] Add backend support for signed loads.

src/compiler/x64/instruction-selector-x64.cc

Index: src/compiler/x64/instruction-selector-x64.cc
diff --git a/src/compiler/x64/instruction-selector-x64.cc b/src/compiler/x64/instruction-selector-x64.cc
index 1dad9ee863ae144b887f856d5bdff5afabb40d4f..138a63d7f7bdac4ece457b603a3bcbe8ecda2394 100644
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -57,6 +57,7 @@ class X64OperandGenerator V8_FINAL : public OperandGenerator {
 
 void InstructionSelector::VisitLoad(Node* node) {
   MachineType rep = RepresentationOf(OpParameter<MachineType>(node));
+  MachineType typ = TypeOf(OpParameter<MachineType>(node));
   X64OperandGenerator g(this);
   Node* base = node->InputAt(0);
   Node* index = node->InputAt(1);
@@ -68,21 +69,21 @@ void InstructionSelector::VisitLoad(Node* node) {
   // TODO(titzer): signed/unsigned small loads
   switch (rep) {
     case kRepFloat64:
-      opcode = kSSELoad;
+      opcode = kX64Movsd;
       break;
     case kRepBit:  // Fall through.
     case kRepWord8:
-      opcode = kX64LoadWord8;
+      opcode = typ == kTypeInt32 ? kX64Movsxbl : kX64Movzxbl;
       break;
     case kRepWord16:
-      opcode = kX64LoadWord16;
+      opcode = typ == kTypeInt32 ? kX64Movsxwl : kX64Movzxwl;
       break;
     case kRepWord32:
-      opcode = kX64LoadWord32;
+      opcode = kX64Movl;
       break;
     case kRepTagged:  // Fall through.
     case kRepWord64:
-      opcode = kX64LoadWord64;
+      opcode = kX64Movq;
       break;
     default:
       UNREACHABLE();
@@ -123,13 +124,11 @@ void InstructionSelector::VisitStore(Node* node) {
     return;
   }
   DCHECK_EQ(kNoWriteBarrier, store_rep.write_barrier_kind);
-  bool is_immediate = false;
   InstructionOperand* val;
   if (rep == kRepFloat64) {
     val = g.UseDoubleRegister(value);
   } else {
-    is_immediate = g.CanBeImmediate(value);
-    if (is_immediate) {
+    if (g.CanBeImmediate(value)) {
       val = g.UseImmediate(value);
     } else if (rep == kRepWord8 || rep == kRepBit) {
       val = g.UseByteRegister(value);
@@ -140,21 +139,21 @@ void InstructionSelector::VisitStore(Node* node) {
   ArchOpcode opcode;
   switch (rep) {
     case kRepFloat64:
-      opcode = kSSEStore;
+      opcode = kX64Movsd;
       break;
     case kRepBit:  // Fall through.
     case kRepWord8:
-      opcode = is_immediate ? kX64StoreWord8I : kX64StoreWord8;
+      opcode = kX64Movb;
       break;
     case kRepWord16:
-      opcode = is_immediate ? kX64StoreWord16I : kX64StoreWord16;
+      opcode = kX64Movw;
       break;
     case kRepWord32:
-      opcode = is_immediate ? kX64StoreWord32I : kX64StoreWord32;
+      opcode = kX64Movl;
       break;
     case kRepTagged:  // Fall through.
     case kRepWord64:
-      opcode = is_immediate ? kX64StoreWord64I : kX64StoreWord64;
+      opcode = kX64Movq;
       break;
     default:
       UNREACHABLE();