45 lines · c
1// Check that omp atomic compare handles signedness of integer comparisons2// correctly.3//4// At one time, a bug sometimes reversed the signedness.5 6// RUN: %libomp-compile7// RUN: %libomp-run | FileCheck %s8 9// This test uses -fopenmp-version, which is not a compiler flag that GCC10// supports.11// UNSUPPORTED: gcc12 13// High parallelism increases our chances of detecting a lack of atomicity.14#define NUM_THREADS_TRY 25615 16#include <limits.h>17#include <omp.h>18#include <stdio.h>19 20int main() {21 // CHECK: signed: num_threads=[[#NUM_THREADS:]]{{$}}22 // CHECK-NEXT: signed: xs=[[#NUM_THREADS-1]]{{$}}23 int xs = -1;24 int numThreads;25 #pragma omp parallel for num_threads(NUM_THREADS_TRY)26 for (int i = 0; i < omp_get_num_threads(); ++i) {27 #pragma omp atomic compare28 if (xs < i) { xs = i; }29 if (i == 0)30 numThreads = omp_get_num_threads();31 }32 printf("signed: num_threads=%d\n", numThreads);33 printf("signed: xs=%d\n", xs);34 35 // CHECK-NEXT: unsigned: xu=0x0{{$}}36 unsigned xu = UINT_MAX;37 #pragma omp parallel for num_threads(NUM_THREADS_TRY)38 for (int i = 0; i < omp_get_num_threads(); ++i) {39 #pragma omp atomic compare40 if (xu > i) { xu = i; }41 }42 printf("unsigned: xu=0x%x\n", xu);43 return 0;44}45