1 files changed, 27 insertions, 33 deletions

diff --git a/third_party/abseil-cpp/absl/time/internal/cctz/include/cctz/civil_time_detail.h b/third_party/abseil-cpp/absl/time/internal/cctz/include/cctz/civil_time_detail.h
index 8aadde57ca..4cde96f1aa 100644
--- a/third_party/abseil-cpp/absl/time/internal/cctz/include/cctz/civil_time_detail.h
+++ b/third_party/abseil-cpp/absl/time/internal/cctz/include/cctz/civil_time_detail.h
@@ -106,64 +106,54 @@ CONSTEXPR_F int days_per_month(year_t y, month_t m) noexcept {
 
 CONSTEXPR_F fields n_day(year_t y, month_t m, diff_t d, diff_t cd, hour_t hh,
                          minute_t mm, second_t ss) noexcept {
-  year_t ey = y % 400;
-  const year_t oey = ey;
-  ey += (cd / 146097) * 400;
+  y += (cd / 146097) * 400;
   cd %= 146097;
   if (cd < 0) {
-    ey -= 400;
+    y -= 400;
     cd += 146097;
   }
-  ey += (d / 146097) * 400;
+  y += (d / 146097) * 400;
   d = d % 146097 + cd;
   if (d > 0) {
     if (d > 146097) {
-      ey += 400;
+      y += 400;
       d -= 146097;
     }
   } else {
     if (d > -365) {
       // We often hit the previous year when stepping a civil time backwards,
       // so special case it to avoid counting up by 100/4/1-year chunks.
-      ey -= 1;
-      d += days_per_year(ey, m);
+      y -= 1;
+      d += days_per_year(y, m);
     } else {
-      ey -= 400;
+      y -= 400;
       d += 146097;
     }
   }
   if (d > 365) {
-    for (;;) {
-      int n = days_per_century(ey, m);
-      if (d <= n) break;
+    for (int n = days_per_century(y, m); d > n; n = days_per_century(y, m)) {
       d -= n;
-      ey += 100;
+      y += 100;
     }
-    for (;;) {
-      int n = days_per_4years(ey, m);
-      if (d <= n) break;
+    for (int n = days_per_4years(y, m); d > n; n = days_per_4years(y, m)) {
       d -= n;
-      ey += 4;
+      y += 4;
     }
-    for (;;) {
-      int n = days_per_year(ey, m);
-      if (d <= n) break;
+    for (int n = days_per_year(y, m); d > n; n = days_per_year(y, m)) {
       d -= n;
-      ++ey;
+      ++y;
     }
   }
   if (d > 28) {
-    for (;;) {
-      int n = days_per_month(ey, m);
-      if (d <= n) break;
+    for (int n = days_per_month(y, m); d > n; n = days_per_month(y, m)) {
       d -= n;
       if (++m > 12) {
-        ++ey;
+        ++y;
         m = 1;
       }
     }
   }
-  return fields(y + (ey - oey), m, static_cast<day_t>(d), hh, mm, ss);
+  return fields(y, m, static_cast<day_t>(d), hh, mm, ss);
 }
 CONSTEXPR_F fields n_mon(year_t y, diff_t m, diff_t d, diff_t cd, hour_t hh,
                          minute_t mm, second_t ss) noexcept {
@@ -416,10 +406,16 @@ class civil_time {
 
   // Assigning arithmetic.
   CONSTEXPR_M civil_time& operator+=(diff_t n) noexcept {
-    return *this = *this + n;
+    f_ = step(T{}, f_, n);
+    return *this;
   }
   CONSTEXPR_M civil_time& operator-=(diff_t n) noexcept {
-    return *this = *this - n;
+    if (n != (std::numeric_limits<diff_t>::min)()) {
+      f_ = step(T{}, f_, -n);
+    } else {
+      f_ = step(T{}, step(T{}, f_, -(n + 1)), 1);
+    }
+    return *this;
   }
   CONSTEXPR_M civil_time& operator++() noexcept { return *this += 1; }
   CONSTEXPR_M civil_time operator++(int) noexcept {
@@ -436,15 +432,13 @@ class civil_time {
 
   // Binary arithmetic operators.
   friend CONSTEXPR_F civil_time operator+(civil_time a, diff_t n) noexcept {
-    return civil_time(step(T{}, a.f_, n));
+    return a += n;
   }
   friend CONSTEXPR_F civil_time operator+(diff_t n, civil_time a) noexcept {
-    return a + n;
+    return a += n;
   }
   friend CONSTEXPR_F civil_time operator-(civil_time a, diff_t n) noexcept {
-    return n != (std::numeric_limits<diff_t>::min)()
-               ? civil_time(step(T{}, a.f_, -n))
-               : civil_time(step(T{}, step(T{}, a.f_, -(n + 1)), 1));
+    return a -= n;
   }
   friend CONSTEXPR_F diff_t operator-(civil_time lhs, civil_time rhs) noexcept {
     return difference(T{}, lhs.f_, rhs.f_);