X87: [turbofan] Add the RoundInt32ToFloat32 operator to turbofan.

src/compiler/x87/code-generator-x87.cc

Index: src/compiler/x87/code-generator-x87.cc
diff --git a/src/compiler/x87/code-generator-x87.cc b/src/compiler/x87/code-generator-x87.cc
index 96e029111bf618ae87a8b15eed96194c4fb3ef09..937d735874c519cb46af4986025d7a719b7c6671 100644
--- a/src/compiler/x87/code-generator-x87.cc
+++ b/src/compiler/x87/code-generator-x87.cc
@@ -972,6 +972,20 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ lea(esp, Operand(esp, kDoubleSize));
       break;
     }
+    case kX87Int32ToFloat32: {
+      InstructionOperand* input = instr->InputAt(0);
+      DCHECK(input->IsRegister() || input->IsStackSlot());
+      __ fstp(0);
+      if (input->IsRegister()) {
+        Register input_reg = i.InputRegister(0);
+        __ push(input_reg);
+        __ fild_s(Operand(esp, 0));
+        __ pop(input_reg);
+      } else {
+        __ fild_s(i.InputOperand(0));
+      }
+      break;
+    }
     case kX87Int32ToFloat64: {
       InstructionOperand* input = instr->InputAt(0);
       DCHECK(input->IsRegister() || input->IsStackSlot());