Optimize `absl::Duration` division and modulo: Avoid repeated redundant…

Optimize `absl::Duration` division and modulo: Avoid repeated redundant comparisons in `IDivFastPath`.

PiperOrigin-RevId: 610758911
Change-Id: I3d0fa2f52a3bd75bdd2b5c365d79878b4160bd29

absl/time/duration.cc

@@ -280,33 +280,35 @@ inline bool IDivFastPath(const Duration num, const Duration den, int64_t* q,
   int64_t den_hi = time_internal::GetRepHi(den);
   uint32_t den_lo = time_internal::GetRepLo(den);
 
-  if (den_hi == 0 && den_lo == kTicksPerNanosecond) {
-    // Dividing by 1ns
-    if (num_hi >= 0 && num_hi < (kint64max - kTicksPerSecond) / 1000000000) {
-      *q = num_hi * 1000000000 + num_lo / kTicksPerNanosecond;
-      *rem = time_internal::MakeDuration(0, num_lo % den_lo);
-      return true;
-    }
-  } else if (den_hi == 0 && den_lo == 100 * kTicksPerNanosecond) {
-    // Dividing by 100ns (common when converting to Universal time)
-    if (num_hi >= 0 && num_hi < (kint64max - kTicksPerSecond) / 10000000) {
-      *q = num_hi * 10000000 + num_lo / (100 * kTicksPerNanosecond);
-      *rem = time_internal::MakeDuration(0, num_lo % den_lo);
-      return true;
-    }
-  } else if (den_hi == 0 && den_lo == 1000 * kTicksPerNanosecond) {
-    // Dividing by 1us
-    if (num_hi >= 0 && num_hi < (kint64max - kTicksPerSecond) / 1000000) {
-      *q = num_hi * 1000000 + num_lo / (1000 * kTicksPerNanosecond);
-      *rem = time_internal::MakeDuration(0, num_lo % den_lo);
-      return true;
-    }
-  } else if (den_hi == 0 && den_lo == 1000000 * kTicksPerNanosecond) {
-    // Dividing by 1ms
-    if (num_hi >= 0 && num_hi < (kint64max - kTicksPerSecond) / 1000) {
-      *q = num_hi * 1000 + num_lo / (1000000 * kTicksPerNanosecond);
-      *rem = time_internal::MakeDuration(0, num_lo % den_lo);
-      return true;
+  if (den_hi == 0) {
+    if (den_lo == kTicksPerNanosecond) {
+      // Dividing by 1ns
+      if (num_hi >= 0 && num_hi < (kint64max - kTicksPerSecond) / 1000000000) {
+        *q = num_hi * 1000000000 + num_lo / kTicksPerNanosecond;
+        *rem = time_internal::MakeDuration(0, num_lo % den_lo);
+        return true;
+      }
+    } else if (den_lo == 100 * kTicksPerNanosecond) {
+      // Dividing by 100ns (common when converting to Universal time)
+      if (num_hi >= 0 && num_hi < (kint64max - kTicksPerSecond) / 10000000) {
+        *q = num_hi * 10000000 + num_lo / (100 * kTicksPerNanosecond);
+        *rem = time_internal::MakeDuration(0, num_lo % den_lo);
+        return true;
+      }
+    } else if (den_lo == 1000 * kTicksPerNanosecond) {
+      // Dividing by 1us
+      if (num_hi >= 0 && num_hi < (kint64max - kTicksPerSecond) / 1000000) {
+        *q = num_hi * 1000000 + num_lo / (1000 * kTicksPerNanosecond);
+        *rem = time_internal::MakeDuration(0, num_lo % den_lo);
+        return true;
+      }
+    } else if (den_lo == 1000000 * kTicksPerNanosecond) {
+      // Dividing by 1ms
+      if (num_hi >= 0 && num_hi < (kint64max - kTicksPerSecond) / 1000) {
+        *q = num_hi * 1000 + num_lo / (1000000 * kTicksPerNanosecond);
+        *rem = time_internal::MakeDuration(0, num_lo % den_lo);
+        return true;
+      }
     }
   } else if (den_hi > 0 && den_lo == 0) {
     // Dividing by positive multiple of 1s