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52ae891036
There are several files in the compiler-rt subproject that have command not found errors. This patch uses the `env` command to properly set the environment variables correctly when using the lit internal shell. fixes: #102395 [This change is relevant [RFC] Enabling the lit internal shell by Default](https://discourse.llvm.org/t/rfc-enabling-the-lit-internal-shell-by-default/80179)
71 lines
2.3 KiB
C++
71 lines
2.3 KiB
C++
// RUN: %clangxx_nsan -O0 -mllvm -nsan-shadow-type-mapping=dqq -g -DSUM=NaiveSum -DFLT=float %s -o %t
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// RUN: env NSAN_OPTIONS=halt_on_error=1,log2_max_relative_error=19 not %run %t 2>&1 | FileCheck %s
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// RUN: %clangxx_nsan -O3 -mllvm -nsan-shadow-type-mapping=dqq -g -DSUM=NaiveSum -DFLT=float %s -o %t
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// RUN: env NSAN_OPTIONS=halt_on_error=1,log2_max_relative_error=19 not %run %t 2>&1 | FileCheck %s
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// RUN: %clangxx_nsan -O0 -mllvm -nsan-shadow-type-mapping=dqq -g -DSUM=KahanSum -DFLT=float %s -o %t
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// RUN: env NSAN_OPTIONS=halt_on_error=1,log2_max_relative_error=19 %run %t
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// RUN: %clangxx_nsan -O3 -mllvm -nsan-shadow-type-mapping=dqq -g -DSUM=KahanSum -DFLT=float %s -o %t
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// RUN: env NSAN_OPTIONS=halt_on_error=1,log2_max_relative_error=19 %run %t
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#include <chrono>
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#include <iostream>
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#include <random>
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#include <vector>
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// A naive, unstable summation.
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template <typename T>
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__attribute__((noinline)) // To check call stack reporting.
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T NaiveSum(const std::vector<T>& values) {
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T sum = 0;
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for (T v : values) {
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sum += v;
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}
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return sum;
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// CHECK: WARNING: NumericalStabilitySanitizer: inconsistent shadow results while checking return
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// CHECK: float{{ *}}precision (native):
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// CHECK: double{{ *}}precision (shadow):
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// CHECK: {{#0 .*in .* NaiveSum}}
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}
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// Kahan's summation is a numerically stable sum.
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// https://en.wikipedia.org/wiki/Kahan_summation_algorithm
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template <typename T>
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__attribute__((noinline)) T KahanSum(const std::vector<T> &values) {
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T sum = 0;
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T c = 0;
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for (T v : values) {
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T y = v - c;
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T t = sum + y;
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c = (t - sum) - y;
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sum = t;
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}
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return sum;
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}
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int main() {
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std::vector<FLT> values;
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constexpr int kNumValues = 1000000;
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values.reserve(kNumValues);
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// Using a seed to avoid flakiness.
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constexpr uint32_t kSeed = 0x123456;
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std::mt19937 gen(kSeed);
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std::uniform_real_distribution<FLT> dis(0.0f, 1000.0f);
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for (int i = 0; i < kNumValues; ++i) {
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values.push_back(dis(gen));
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}
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const auto t1 = std::chrono::high_resolution_clock::now();
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const auto sum = SUM(values);
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const auto t2 = std::chrono::high_resolution_clock::now();
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printf("sum: %.8f\n", sum);
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std::cout << "runtime: "
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<< std::chrono::duration_cast<std::chrono::microseconds>(t2 - t1)
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.count() /
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1000.0
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<< "ms\n";
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return 0;
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}
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