[llvm] f5ef9bd - [memprof] Call SmallVector::reserve (#86055)

[via llvm-commits]

Author: Kazu Hirata
Date: 2024-03-21T11:17:52-07:00
New Revision: f5ef9bd26d531d104f44f9e5b283bd2f80c024be

URL: https://github.com/llvm/llvm-project/commit/f5ef9bd26d531d104f44f9e5b283bd2f80c024be
DIFF: https://github.com/llvm/llvm-project/commit/f5ef9bd26d531d104f44f9e5b283bd2f80c024be.diff

LOG: [memprof] Call SmallVector::reserve (#86055)

With one raw memprof file I have, NumPCs averages about 41.  Given the
default number of inline elements being 8 for SmallVector<uint64_t>,
we should reserve the storage in advance.

Added: 
    

Modified: 
    llvm/lib/ProfileData/RawMemProfReader.cpp

Removed: 
    


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diff  --git a/llvm/lib/ProfileData/RawMemProfReader.cpp b/llvm/lib/ProfileData/RawMemProfReader.cpp
index 0e2b8668bab72c..60c37c417aa049 100644
--- a/llvm/lib/ProfileData/RawMemProfReader.cpp
+++ b/llvm/lib/ProfileData/RawMemProfReader.cpp
@@ -127,6 +127,7 @@ CallStackMap readStackInfo(const char *Ptr) {
         endian::readNext<uint64_t, llvm::endianness::little, unaligned>(Ptr);
 
     SmallVector<uint64_t> CallStack;
+    CallStack.reserve(NumPCs);
     for (uint64_t J = 0; J < NumPCs; J++) {
       CallStack.push_back(
           endian::readNext<uint64_t, llvm::endianness::little, unaligned>(Ptr));