[libcxx-commits] [libcxx] c25e09e - [libc++][test] Speed up input generating functions for benchmark tests (#115544)

[via libcxx-commits]

Author: Peng Liu
Date: 2024-11-18T16:32:54+01:00
New Revision: c25e09e238c6f872a116d10bbefba0beff145a57

URL: https://github.com/llvm/llvm-project/commit/c25e09e238c6f872a116d10bbefba0beff145a57
DIFF: https://github.com/llvm/llvm-project/commit/c25e09e238c6f872a116d10bbefba0beff145a57.diff

LOG: [libc++][test] Speed up input generating functions for benchmark tests (#115544)

The input generating functions for benchmark tests in the GenerateInput.h
file can be slightly improved by invoking vector::reserve before calling
vector::push_back. This slight performance improvement could potentially
speed-up all benchmark tests for containers and algorithms that use these
functions as inputs.

Added: 
    

Modified: 
    libcxx/test/benchmarks/GenerateInput.h

Removed: 
    


################################################################################
diff  --git a/libcxx/test/benchmarks/GenerateInput.h b/libcxx/test/benchmarks/GenerateInput.h
index 0f3e9309271bb1..db376614382bc4 100644
--- a/libcxx/test/benchmarks/GenerateInput.h
+++ b/libcxx/test/benchmarks/GenerateInput.h
@@ -53,6 +53,7 @@ inline std::vector<IntT> getDuplicateIntegerInputs(std::size_t N) {
 template <class IntT>
 inline std::vector<IntT> getSortedIntegerInputs(std::size_t N) {
   std::vector<IntT> inputs;
+  inputs.reserve(N);
   for (std::size_t i = 0; i < N; i += 1)
     inputs.push_back(i);
   return inputs;
@@ -61,6 +62,7 @@ inline std::vector<IntT> getSortedIntegerInputs(std::size_t N) {
 template <class IntT>
 std::vector<IntT> getSortedLargeIntegerInputs(std::size_t N) {
   std::vector<IntT> inputs;
+  inputs.reserve(N);
   for (std::size_t i = 0; i < N; ++i)
     inputs.push_back(i + N);
   return inputs;
@@ -77,6 +79,7 @@ std::vector<IntT> getSortedTopBitsIntegerInputs(std::size_t N) {
 template <class IntT>
 inline std::vector<IntT> getReverseSortedIntegerInputs(std::size_t N) {
   std::vector<IntT> inputs;
+  inputs.reserve(N);
   std::size_t i = N;
   while (i > 0) {
     --i;
@@ -99,6 +102,7 @@ std::vector<IntT> getPipeOrganIntegerInputs(std::size_t N) {
 template <class IntT>
 std::vector<IntT> getRandomIntegerInputs(std::size_t N) {
   std::vector<IntT> inputs;
+  inputs.reserve(N);
   for (std::size_t i = 0; i < N; ++i)
     inputs.push_back(getRandomInteger<IntT>(0, std::numeric_limits<IntT>::max()));
   return inputs;
@@ -111,6 +115,7 @@ inline std::vector<std::string> getDuplicateStringInputs(std::size_t N) {
 
 inline std::vector<std::string> getRandomStringInputs(std::size_t N) {
   std::vector<std::string> inputs;
+  inputs.reserve(N);
   for (std::size_t i = 0; i < N; ++i)
     inputs.push_back(getRandomString(1024));
   return inputs;
@@ -118,6 +123,7 @@ inline std::vector<std::string> getRandomStringInputs(std::size_t N) {
 
 inline std::vector<std::string> getPrefixedRandomStringInputs(std::size_t N) {
   std::vector<std::string> inputs;
+  inputs.reserve(N);
   constexpr int kSuffixLength = 32;
   const std::string prefix    = getRandomString(1024 - kSuffixLength);
   for (std::size_t i = 0; i < N; ++i)