[llvm] 4d04526 - ADT: Avoid using SmallVector::set_size() in SmallString

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

Author: Duncan P. N. Exon Smith
Date: 2022-01-11T17:33:13-08:00
New Revision: 4d04526bf48d982055fd625803734b2afded3afb

URL: https://github.com/llvm/llvm-project/commit/4d04526bf48d982055fd625803734b2afded3afb
DIFF: https://github.com/llvm/llvm-project/commit/4d04526bf48d982055fd625803734b2afded3afb.diff

LOG: ADT: Avoid using SmallVector::set_size() in SmallString

Update `SmallString::append()` to use `resize_for_overwrite()` instead
of `reserve()` followed by `set_size()`.

Differential Revision: https://reviews.llvm.org/D115382

Added: 
    

Modified: 
    llvm/include/llvm/ADT/SmallString.h

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/ADT/SmallString.h b/llvm/include/llvm/ADT/SmallString.h
index 56b0639b98cc3..81243af1f97d2 100644
--- a/llvm/include/llvm/ADT/SmallString.h
+++ b/llvm/include/llvm/ADT/SmallString.h
@@ -70,16 +70,16 @@ class SmallString : public SmallVector<char, InternalLen> {
 
   /// Append from a list of StringRefs.
   void append(std::initializer_list<StringRef> Refs) {
-    size_t SizeNeeded = this->size();
+    size_t CurrentSize = this->size();
+    size_t SizeNeeded = CurrentSize;
     for (const StringRef &Ref : Refs)
       SizeNeeded += Ref.size();
-    this->reserve(SizeNeeded);
-    auto CurEnd = this->end();
+    this->resize_for_overwrite(SizeNeeded);
     for (const StringRef &Ref : Refs) {
-      this->uninitialized_copy(Ref.begin(), Ref.end(), CurEnd);
-      CurEnd += Ref.size();
+      std::copy(Ref.begin(), Ref.end(), this->begin() + CurrentSize);
+      CurrentSize += Ref.size();
     }
-    this->set_size(SizeNeeded);
+    assert(CurrentSize == this->size());
   }
 
   /// @}