[turbofan] Add backend support for load/store float32 values.

src/compiler/x64/code-generator-x64.cc

Index: src/compiler/x64/code-generator-x64.cc
diff --git a/src/compiler/x64/code-generator-x64.cc b/src/compiler/x64/code-generator-x64.cc
index 950652546880ae8bb4c311ffcbc37a6c4344158a..5743cd71389c51bcb17a112e2bfa0b130cd38727 100644
--- a/src/compiler/x64/code-generator-x64.cc
+++ b/src/compiler/x64/code-generator-x64.cc
@@ -514,15 +514,6 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       break;
     }
 
-    case kX64Movsd:
-      if (instr->HasOutput()) {
-        __ movsd(i.OutputDoubleRegister(), i.MemoryOperand());
-      } else {
-        int index = 0;
-        Operand operand = i.MemoryOperand(&index);
-        __ movsd(operand, i.InputDoubleRegister(index));
-      }
-      break;
     case kX64Movsxbl:
       __ movsxbl(i.OutputRegister(), i.MemoryOperand());
       break;
@@ -599,6 +590,26 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
         }
       }
       break;
+    case kX64Movss:
+      if (instr->HasOutput()) {
+        __ movss(i.OutputDoubleRegister(), i.MemoryOperand());
+        __ cvtss2sd(i.OutputDoubleRegister(), i.OutputDoubleRegister());
+      } else {
+        int index = 0;
+        Operand operand = i.MemoryOperand(&index);
+        __ cvtsd2ss(xmm0, i.InputDoubleRegister(index));
+        __ movss(operand, xmm0);
+      }
+      break;
+    case kX64Movsd:
+      if (instr->HasOutput()) {
+        __ movsd(i.OutputDoubleRegister(), i.MemoryOperand());
+      } else {
+        int index = 0;
+        Operand operand = i.MemoryOperand(&index);
+        __ movsd(operand, i.InputDoubleRegister(index));
+      }
+      break;
     case kX64StoreWriteBarrier: {
       Register object = i.InputRegister(0);
       Register index = i.InputRegister(1);