Add `MaskFull` to `Group`.

It is not used at the moment. Usage is planned to be submitted separately.

Useful for faster iterating over all slots in the internal functions.

PiperOrigin-RevId: 590300049
Change-Id: I081f33113268761db868771d29796d94c24e4e7a

absl/container/internal/raw_hash_set.h

@@ -637,6 +637,14 @@ struct GroupSse2Impl {
 #endif
   }
 
+  // Returns a bitmask representing the positions of full slots.
+  // Note: for `is_small()` tables group may contain the "same" slot twice:
+  // original and mirrored.
+  BitMask<uint16_t, kWidth> MaskFull() const {
+    return BitMask<uint16_t, kWidth>(
+        static_cast<uint16_t>(_mm_movemask_epi8(ctrl) ^ 0xffff));
+  }
+
   // Returns a bitmask representing the positions of empty or deleted slots.
   NonIterableBitMask<uint16_t, kWidth> MaskEmptyOrDeleted() const {
     auto special = _mm_set1_epi8(static_cast<char>(ctrl_t::kSentinel));
@@ -692,6 +700,17 @@ struct GroupAArch64Impl {
     return NonIterableBitMask<uint64_t, kWidth, 3>(mask);
   }
 
+  // Returns a bitmask representing the positions of full slots.
+  // Note: for `is_small()` tables group may contain the "same" slot twice:
+  // original and mirrored.
+  BitMask<uint64_t, kWidth, 3> MaskFull() const {
+    uint64_t mask = vget_lane_u64(
+        vreinterpret_u64_u8(vcge_s8(vreinterpret_s8_u8(ctrl),
+                                    vdup_n_s8(static_cast<int8_t>(0)))),
+        0);
+    return BitMask<uint64_t, kWidth, 3>(mask);
+  }
+
   NonIterableBitMask<uint64_t, kWidth, 3> MaskEmptyOrDeleted() const {
     uint64_t mask =
         vget_lane_u64(vreinterpret_u64_u8(vcgt_s8(
@@ -760,6 +779,14 @@ struct GroupPortableImpl {
                                                    msbs);
   }
 
+  // Returns a bitmask representing the positions of full slots.
+  // Note: for `is_small()` tables group may contain the "same" slot twice:
+  // original and mirrored.
+  BitMask<uint64_t, kWidth, 3> MaskFull() const {
+    constexpr uint64_t msbs = 0x8080808080808080ULL;
+    return BitMask<uint64_t, kWidth, 3>((ctrl ^ msbs) & msbs);
+  }
+
   NonIterableBitMask<uint64_t, kWidth, 3> MaskEmptyOrDeleted() const {
     constexpr uint64_t msbs = 0x8080808080808080ULL;
     return NonIterableBitMask<uint64_t, kWidth, 3>((ctrl & ~(ctrl << 7)) &

absl/container/internal/raw_hash_set_test.cc

@@ -232,6 +232,25 @@ TEST(Group, MaskEmpty) {
   }
 }
 
+TEST(Group, MaskFull) {
+  if (Group::kWidth == 16) {
+    ctrl_t group[] = {
+        ctrl_t::kEmpty, CtrlT(1),          ctrl_t::kDeleted,  CtrlT(3),
+        ctrl_t::kEmpty, CtrlT(5),          ctrl_t::kSentinel, CtrlT(7),
+        CtrlT(7),       CtrlT(5),          ctrl_t::kDeleted,  CtrlT(1),
+        CtrlT(1),       ctrl_t::kSentinel, ctrl_t::kEmpty,    CtrlT(1)};
+    EXPECT_THAT(Group{group}.MaskFull(),
+                ElementsAre(1, 3, 5, 7, 8, 9, 11, 12, 15));
+  } else if (Group::kWidth == 8) {
+    ctrl_t group[] = {ctrl_t::kEmpty,    CtrlT(1), ctrl_t::kEmpty,
+                      ctrl_t::kDeleted,  CtrlT(2), ctrl_t::kSentinel,
+                      ctrl_t::kSentinel, CtrlT(1)};
+    EXPECT_THAT(Group{group}.MaskFull(), ElementsAre(1, 4, 7));
+  } else {
+    FAIL() << "No test coverage for Group::kWidth==" << Group::kWidth;
+  }
+}
+
 TEST(Group, MaskEmptyOrDeleted) {
   if (Group::kWidth == 16) {
     ctrl_t group[] = {ctrl_t::kEmpty,   CtrlT(1), ctrl_t::kEmpty,    CtrlT(3),
@@ -294,8 +313,8 @@ TEST(Group, CountLeadingEmptyOrDeleted) {
       std::vector<ctrl_t> f(Group::kWidth, empty);
       f[Group::kWidth * 2 / 3] = full;
       f[Group::kWidth / 2] = full;
-      EXPECT_EQ(
-          Group::kWidth / 2, Group{f.data()}.CountLeadingEmptyOrDeleted());
+      EXPECT_EQ(Group::kWidth / 2,
+                Group{f.data()}.CountLeadingEmptyOrDeleted());
     }
   }
 }
@@ -433,7 +452,8 @@ struct CustomAlloc : std::allocator<T> {
   template <typename U>
   explicit CustomAlloc(const CustomAlloc<U>& /*other*/) {}
 
-  template<class U> struct rebind {
+  template <class U>
+  struct rebind {
     using other = CustomAlloc<U>;
   };
 };
@@ -1361,15 +1381,15 @@ ExpectedStats XorSeedExpectedStats() {
   switch (container_internal::Group::kWidth) {
     case 8:
       if (kRandomizesInserts) {
-  return {0.05,
-          1.0,
-          {{0.95, 0.5}},
-          {{0.95, 0}, {0.99, 2}, {0.999, 4}, {0.9999, 10}}};
+        return {0.05,
+                1.0,
+                {{0.95, 0.5}},
+                {{0.95, 0}, {0.99, 2}, {0.999, 4}, {0.9999, 10}}};
       } else {
-  return {0.05,
-          2.0,
-          {{0.95, 0.1}},
-          {{0.95, 0}, {0.99, 2}, {0.999, 4}, {0.9999, 10}}};
+        return {0.05,
+                2.0,
+                {{0.95, 0.1}},
+                {{0.95, 0}, {0.99, 2}, {0.999, 4}, {0.9999, 10}}};
       }
     case 16:
       if (kRandomizesInserts) {
@@ -1415,7 +1435,7 @@ ProbeStats CollectProbeStatsOnLinearlyTransformedKeys(
   std::random_device rd;
   std::mt19937 rng(rd());
   auto linear_transform = [](size_t x, size_t y) { return x * 17 + y * 13; };
-  std::uniform_int_distribution<size_t> dist(0, keys.size()-1);
+  std::uniform_int_distribution<size_t> dist(0, keys.size() - 1);
   while (num_iters--) {
     IntTable t1;
     size_t num_keys = keys.size() / 10;