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Elide zero checks in absl::bit_width. #469

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Merged
copybara-service merged 1 commit into from
Aug 10, 2026
+4 −2
Merged

Elide zero checks in absl::bit_width. #469

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6 changes: 4 additions & 2 deletions tcmalloc/central_freelist.h
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Original file line number Diff line number Diff line change
Expand Up @@ -737,6 +737,9 @@ inline int CentralFreeList<Forwarder>::RemoveRange(absl::Span<void*> batch) {
}

const uint16_t prev_allocated = span->Allocated();
#ifndef TCMALLOC_INTERNAL_LEGACY_LOCKING
ASSUME(prev_allocated > 0);
#endif
const uint8_t prev_bitwidth = absl::bit_width(prev_allocated);
TC_ASSERT_EQ(prev_index, span->nonempty_index());
#ifdef TCMALLOC_INTERNAL_LEGACY_LOCKING
Expand All @@ -753,8 +756,7 @@ inline int CentralFreeList<Forwarder>::RemoveRange(absl::Span<void*> batch) {
ASSUME(result < size);
#endif
int here = span->FreelistPopBatch(batch.subspan(result), object_size);
// TODO(b/451807659): Return this to an assert after debugging is done.
TC_CHECK_GT(here, 0, "Failed to make progress. Freelist corrupted?");
ASSUME(here > 0 && "Failed to make progress. Freelist corrupted?");
// As the objects are being popped from the span, its utilization might
// change. So, we remove the stale utilization from the histogram here and
// add it again once we pop the objects.
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