From 8a3caf7dea955b513a6c1b572a2423c6b4213402 Mon Sep 17 00:00:00 2001
From: Abseil Team <absl-team@google.com>
Date: Thu, 15 Feb 2024 23:54:17 -0800
Subject: Introduce `Group::MaskNonFull` without usage.

It can be used instead of `MaskEmptyOrDeleted` in case of inserting to empty table.
`MaskNonFull` requires less operations, in particular it eliminates `_mm_set1_epi8` and `_mm_cmpgt_epi8` operations.

PiperOrigin-RevId: 607587394
Change-Id: Ia48f922d1ca6de38cc91e7ab0d608c45f8f2c446
---
 absl/container/internal/raw_hash_set.h | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

(limited to 'absl/container/internal/raw_hash_set.h')

diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h
index d6950e61..cef042e7 100644
--- a/absl/container/internal/raw_hash_set.h
+++ b/absl/container/internal/raw_hash_set.h
@@ -657,6 +657,14 @@ struct GroupSse2Impl {
         static_cast<uint16_t>(_mm_movemask_epi8(ctrl) ^ 0xffff));
   }
 
+  // Returns a bitmask representing the positions of non full slots.
+  // Note: this includes: kEmpty, kDeleted, kSentinel.
+  // It is useful in contexts when kSentinel is not present.
+  auto MaskNonFull() const {
+    return BitMask<uint16_t, kWidth>(
+        static_cast<uint16_t>(_mm_movemask_epi8(ctrl)));
+  }
+
   // 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));
@@ -725,6 +733,18 @@ struct GroupAArch64Impl {
                    /*NullifyBitsOnIteration=*/true>(mask);
   }
 
+  // Returns a bitmask representing the positions of non full slots.
+  // Note: this includes: kEmpty, kDeleted, kSentinel.
+  // It is useful in contexts when kSentinel is not present.
+  auto MaskNonFull() const {
+    uint64_t mask = vget_lane_u64(
+        vreinterpret_u64_u8(vclt_s8(vreinterpret_s8_u8(ctrl),
+                                    vdup_n_s8(static_cast<int8_t>(0)))),
+        0);
+    return BitMask<uint64_t, kWidth, /*Shift=*/3,
+                   /*NullifyBitsOnIteration=*/true>(mask);
+  }
+
   NonIterableBitMask<uint64_t, kWidth, 3> MaskEmptyOrDeleted() const {
     uint64_t mask =
         vget_lane_u64(vreinterpret_u64_u8(vcgt_s8(
@@ -797,6 +817,13 @@ struct GroupPortableImpl {
     return BitMask<uint64_t, kWidth, 3>((ctrl ^ kMsbs8Bytes) & kMsbs8Bytes);
   }
 
+  // Returns a bitmask representing the positions of non full slots.
+  // Note: this includes: kEmpty, kDeleted, kSentinel.
+  // It is useful in contexts when kSentinel is not present.
+  auto MaskNonFull() const {
+    return BitMask<uint64_t, kWidth, 3>(ctrl  & kMsbs8Bytes);
+  }
+
   NonIterableBitMask<uint64_t, kWidth, 3> MaskEmptyOrDeleted() const {
     return NonIterableBitMask<uint64_t, kWidth, 3>((ctrl & ~(ctrl << 7)) &
                                                    kMsbs8Bytes);
-- 
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