Use realloc instead of malloc+memcpy when growing a POD SmallVector. A smart
realloc implementation can try to expand the allocated memory block in-place,
avoiding the copy.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105605 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/SmallVector.cpp b/lib/Support/SmallVector.cpp
index 6821382..2e17af8 100644
--- a/lib/Support/SmallVector.cpp
+++ b/lib/Support/SmallVector.cpp
@@ -21,15 +21,18 @@
size_t NewCapacityInBytes = 2 * capacity_in_bytes();
if (NewCapacityInBytes < MinSizeInBytes)
NewCapacityInBytes = MinSizeInBytes;
- void *NewElts = operator new(NewCapacityInBytes);
-
- // Copy the elements over. No need to run dtors on PODs.
- memcpy(NewElts, this->BeginX, CurSizeBytes);
-
- // If this wasn't grown from the inline copy, deallocate the old space.
- if (!this->isSmall())
- operator delete(this->BeginX);
-
+
+ void *NewElts;
+ if (this->isSmall()) {
+ NewElts = malloc(NewCapacityInBytes);
+
+ // Copy the elements over. No need to run dtors on PODs.
+ memcpy(NewElts, this->BeginX, CurSizeBytes);
+ } else {
+ // If this wasn't grown from the inline copy, grow the allocated space.
+ NewElts = realloc(this->BeginX, NewCapacityInBytes);
+ }
+
this->EndX = (char*)NewElts+CurSizeBytes;
this->BeginX = NewElts;
this->CapacityX = (char*)this->BeginX + NewCapacityInBytes;