fix sign comparison warnings

llvm-svn: 290469
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: aec0878403f76efcbb84ca6155adb1c54945853e
diff --git a/include/regex b/include/regex
index baff5d3..1c4cc1d 100644
--- a/include/regex
+++ b/include/regex
@@ -6186,7 +6186,7 @@
     _Position         __position_;
     const value_type* __result_;
     value_type        __suffix_;
-    ptrdiff_t         _N_;
+    ptrdiff_t         __n_;
     vector<int>       __subs_;
 
 public:
@@ -6269,10 +6269,10 @@
 private:
     void __init(_BidirectionalIterator __a, _BidirectionalIterator __b);
     void __establish_result () {
-        if (__subs_[_N_] == -1)
+        if (__subs_[__n_] == -1)
             __result_ = &__position_->prefix();
         else
-            __result_ = &(*__position_)[__subs_[_N_]];
+            __result_ = &(*__position_)[__subs_[__n_]];
         }       
 };
 
@@ -6281,7 +6281,7 @@
     regex_token_iterator()
     : __result_(nullptr),
       __suffix_(),
-      _N_(0)
+      __n_(0)
 {
 }
 
@@ -6292,7 +6292,7 @@
 {
     if (__position_ != _Position())
         __establish_result ();
-    else if (__subs_[_N_] == -1)
+    else if (__subs_[__n_] == -1)
     {
         __suffix_.matched = true;
         __suffix_.first = __a;
@@ -6309,7 +6309,7 @@
                          const regex_type& __re, int __submatch,
                          regex_constants::match_flag_type __m)
     : __position_(__a, __b, __re, __m),
-      _N_(0),
+      __n_(0),
       __subs_(1, __submatch)
 {
     __init(__a, __b);
@@ -6321,7 +6321,7 @@
                          const regex_type& __re, const vector<int>& __submatches,
                          regex_constants::match_flag_type __m)
     : __position_(__a, __b, __re, __m),
-      _N_(0),
+      __n_(0),
       __subs_(__submatches)
 {
     __init(__a, __b);
@@ -6336,7 +6336,7 @@
                          initializer_list<int> __submatches,
                          regex_constants::match_flag_type __m)
     : __position_(__a, __b, __re, __m),
-      _N_(0),
+      __n_(0),
       __subs_(__submatches)
 {
     __init(__a, __b);
@@ -6352,7 +6352,7 @@
                              const int (&__submatches)[_Np],
                              regex_constants::match_flag_type __m)
     : __position_(__a, __b, __re, __m),
-      _N_(0),
+      __n_(0),
       __subs_(__submatches, __submatches + _Np)
 {
     __init(__a, __b);
@@ -6364,7 +6364,7 @@
     : __position_(__x.__position_),
       __result_(__x.__result_),
       __suffix_(__x.__suffix_),
-      _N_(__x._N_),
+      __n_(__x.__n_),
       __subs_(__x.__subs_)
 {
     if (__x.__result_ == &__x.__suffix_)
@@ -6386,7 +6386,7 @@
         else
             __result_ = __x.__result_;
         __suffix_ = __x.__suffix_;
-        _N_ = __x._N_;
+        __n_ = __x.__n_;
         __subs_ = __x.__subs_;
 
         if ( __result_ != nullptr && __result_ != &__suffix_ )
@@ -6409,7 +6409,7 @@
         return false;
     if (__result_ == &__suffix_ || __x.__result_ == &__x.__suffix_)
         return false;
-    return __position_ == __x.__position_ && _N_ == __x._N_ &&
+    return __position_ == __x.__position_ && __n_ == __x.__n_ &&
            __subs_ == __x.__subs_;
 }
 
@@ -6420,14 +6420,14 @@
     _Position __prev = __position_;
     if (__result_ == &__suffix_)
         __result_ = nullptr;
-    else if (_N_ + 1 < __subs_.size())
+    else if (static_cast<size_t>(__n_ + 1) < __subs_.size())
     {
-        ++_N_;
+        ++__n_;
         __establish_result();
     }
     else
     {
-        _N_ = 0;
+        __n_ = 0;
         ++__position_;
         if (__position_ != _Position())
             __establish_result();