commit 9bbbbd3b055b7657cace69fb60d60bcb06844601
author Abseil Team <absl-team@google.com> Tue Feb 27 08:22:47 2024 -0800
committer Copybara-Service <copybara-worker@google.com> Tue Feb 27 08:23:28 2024 -0800
tree c841228cf08c21997f5aaa402e9ebd8e57a71b64
parent bde089f91c7da54aea5b3694c6ce58cb020e06fe

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

PiperOrigin-RevId: 610758911
Change-Id: I3d0fa2f52a3bd75bdd2b5c365d79878b4160bd29

absl/time/duration.cc

diff --git a/absl/time/duration.cc b/absl/time/duration.cc
index 4c25dc4..8d0b66f 100644
--- a/absl/time/duration.cc
+++ b/absl/time/duration.cc
@@ -280,33 +280,35 @@
   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