X87: [turbofan] Add RoundUint32ToFloat32 operator to Turbofan.

  port 187b3f28 (r33796)

  original commit message:

BUG=

Review URL: https://codereview.chromium.org/1700583002

Cr-Commit-Position: refs/heads/master@{#33967}

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

@@ -1114,6 +1114,49 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       }
       break;
     }
+    case kX87Uint32ToFloat32: {
+      InstructionOperand* input = instr->InputAt(0);
+      DCHECK(input->IsRegister() || input->IsStackSlot());
+      if (FLAG_debug_code && FLAG_enable_slow_asserts) {
+        __ VerifyX87StackDepth(1);
+      }
+      __ fstp(0);
+      Label msb_set_src;
+      Label jmp_return;
+      // Put input integer into eax(tmporarilly)
+      __ push(eax);
+      if (input->IsRegister())
+        __ mov(eax, i.InputRegister(0));
+      else
+        __ mov(eax, i.InputOperand(0));
+
+      __ test(eax, eax);
+      __ j(sign, &msb_set_src, Label::kNear);
+      __ push(eax);
+      __ fild_s(Operand(esp, 0));
+      __ pop(eax);
+
+      __ jmp(&jmp_return, Label::kNear);
+      __ bind(&msb_set_src);
+      // Need another temp reg
+      __ push(ebx);
+      __ mov(ebx, eax);
+      __ shr(eax, 1);
+      // Recover the least significant bit to avoid rounding errors.
+      __ and_(ebx, Immediate(1));
+      __ or_(eax, ebx);
+      __ push(eax);
+      __ fild_s(Operand(esp, 0));
+      __ pop(eax);
+      __ fld(0);
+      __ faddp();
+      // Restore the ebx
+      __ pop(ebx);
+      __ bind(&jmp_return);
+      // Restore the eax
+      __ pop(eax);
+      break;
+    }
     case kX87Int32ToFloat64: {
       InstructionOperand* input = instr->InputAt(0);
       DCHECK(input->IsRegister() || input->IsStackSlot());

src/compiler/x87/instruction-codes-x87.h

@@ -54,6 +54,7 @@ namespace compiler {
   V(X87Float64Min)                 \
   V(X87Float64Abs)                 \
   V(X87Int32ToFloat32)             \
+  V(X87Uint32ToFloat32)            \
   V(X87Int32ToFloat64)             \
   V(X87Float32ToFloat64)           \
   V(X87Uint32ToFloat64)            \
@@ -86,7 +87,6 @@ namespace compiler {
   V(X87Poke)                       \
   V(X87StackCheck)
 
-
 // Addressing modes represent the "shape" of inputs to an instruction.
 // Many instructions support multiple addressing modes. Addressing modes
 // are encoded into the InstructionCode of the instruction and tell the

src/compiler/x87/instruction-selector-x87.cc

@@ -664,7 +664,9 @@ void InstructionSelector::VisitRoundInt32ToFloat32(Node* node) {
 
 
 void InstructionSelector::VisitRoundUint32ToFloat32(Node* node) {
-  UNIMPLEMENTED();
+  X87OperandGenerator g(this);
+  Emit(kX87Uint32ToFloat32, g.DefineAsFixed(node, stX_0),
+       g.Use(node->InputAt(0)));
 }