[PATCH] D90576: [ADT] Add SmallVector::pop_back_n

[Nathan James via Phabricator via llvm-commits]

njames93 created this revision.
njames93 added a reviewer: dblaikie.
Herald added subscribers: llvm-commits, dexonsmith.
Herald added a project: LLVM.
njames93 requested review of this revision.

Adds a pop_back_n, this is more expressive than using Vec.resize(Vec.size() - N) or a chain or loop of calls to pop_back.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D90576

Files:
  llvm/include/llvm/ADT/SmallVector.h
  llvm/unittests/ADT/SmallVectorTest.cpp


Index: llvm/unittests/ADT/SmallVectorTest.cpp
===================================================================
--- llvm/unittests/ADT/SmallVectorTest.cpp
+++ llvm/unittests/ADT/SmallVectorTest.cpp
@@ -261,8 +261,7 @@
   this->assertValuesInOrder(this->theVector, 2u, 2, 1);
 
   // Pop remaining elements
-  this->theVector.pop_back();
-  this->theVector.pop_back();
+  this->theVector.pop_back_n(2);
   this->assertEmpty(this->theVector);
 
   // Check number of constructor calls. Should be 2 for each list element,
Index: llvm/include/llvm/ADT/SmallVector.h
===================================================================
--- llvm/include/llvm/ADT/SmallVector.h
+++ llvm/include/llvm/ADT/SmallVector.h
@@ -424,6 +424,12 @@
       this->grow(N);
   }
 
+  void pop_back_n(size_type NumItems) {
+    assert(this->size() >= NumItems);
+    this->destroy_range(this->end() - NumItems, this->end());
+    this->set_size(this->size() - NumItems);
+  }
+
   LLVM_NODISCARD T pop_back_val() {
     T Result = ::std::move(this->back());
     this->pop_back();


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