[PATCH] D91832: ADT: Weaken SmallVector::resize assertion from 5abf76fbe37380874a88cc9aa02164800e4e10f3

[Duncan P. N. Exon Smith via Phabricator via llvm-commits]

dexonsmith created this revision.
dexonsmith added reviewers: mehdi_amini, dblaikie, njames93, silvas.
Herald added a subscriber: ributzka.
Herald added a project: LLVM.
dexonsmith requested review of this revision.

There's no need to check for reference invalidation when
`SmallVector::resize` is shrinking; the parameter isn't accessed.


https://reviews.llvm.org/D91832

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
@@ -1060,9 +1060,13 @@
 TYPED_TEST(SmallVectorReferenceInvalidationTest, Resize) {
   auto &V = this->V;
   (void)V;
+  int N = this->NumBuiltinElts(V);
 #if !defined(NDEBUG) && GTEST_HAS_DEATH_TEST
-  EXPECT_DEATH(V.resize(2, V.back()), this->AssertionMessage);
+  EXPECT_DEATH(V.resize(N + 1, V.back()), this->AssertionMessage);
 #endif
+
+  // No assertion when shrinking, since the parameter isn't accessed.
+  V.resize(N - 1, V.back());
 }
 
 TYPED_TEST(SmallVectorReferenceInvalidationTest, Append) {
Index: llvm/include/llvm/ADT/SmallVector.h
===================================================================
--- llvm/include/llvm/ADT/SmallVector.h
+++ llvm/include/llvm/ADT/SmallVector.h
@@ -521,11 +521,11 @@
   }
 
   void resize(size_type N, const T &NV) {
-    this->assertSafeToReferenceAfterResize(&NV, N);
     if (N < this->size()) {
       this->destroy_range(this->begin()+N, this->end());
       this->set_size(N);
     } else if (N > this->size()) {
+      this->assertSafeToReferenceAfterResize(&NV, N);
       if (this->capacity() < N)
         this->grow(N);
       std::uninitialized_fill(this->end(), this->begin()+N, NV);


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