[turbofan] remove checks for virtual register overflow

src/compiler/register-allocator.h

Index: src/compiler/register-allocator.h
diff --git a/src/compiler/register-allocator.h b/src/compiler/register-allocator.h
index b17837ba59efe89a32a948bd79ee6be240f5a2c1..b8219882fcc1c976ce20104ee96138e7e22b0abb 100644
--- a/src/compiler/register-allocator.h
+++ b/src/compiler/register-allocator.h
@@ -377,8 +377,6 @@ class RegisterAllocator FINAL : public ZoneObject {
                              InstructionSequence* code,
                              const char* debug_name = nullptr);
 
-  bool AllocationOk() { return allocation_ok_; }
-
   const ZoneVector<LiveRange*>& live_ranges() const { return live_ranges_; }
   const ZoneVector<LiveRange*>& fixed_live_ranges() const {
     return fixed_live_ranges_;
@@ -421,15 +419,7 @@ class RegisterAllocator FINAL : public ZoneObject {
   void ResolveControlFlow();
 
  private:
-  int GetVirtualRegister() {
-    int vreg = code()->NextVirtualRegister();
-    if (vreg >= UnallocatedOperand::kMaxVirtualRegisters) {
-      allocation_ok_ = false;
-      // Maintain the invariant that we return something below the maximum.
-      return 0;
-    }
-    return vreg;
-  }
+  int GetVirtualRegister() { return code()->NextVirtualRegister(); }
 
   // Checks whether the value of a given virtual register is a reference.
   // TODO(titzer): rename this to IsReference.
@@ -625,9 +615,6 @@ class RegisterAllocator FINAL : public ZoneObject {
   BitVector* assigned_registers_;
   BitVector* assigned_double_registers_;
 
-  // Indicates success or failure during register allocation.
-  bool allocation_ok_;
-
 #ifdef DEBUG
   LifetimePosition allocation_finger_;
 #endif