| 1 | // Check that omp atomic compare handles signedness of integer comparisons |
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| 2 | // correctly. |
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| 3 | // |
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| 4 | // At one time, a bug sometimes reversed the signedness. |
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| 5 | |
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| 6 | // RUN: %libomp-compile |
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| 7 | // RUN: %libomp-run | FileCheck %s |
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| 8 | |
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| 9 | // This test uses -fopenmp-version, which is not a compiler flag that GCC |
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| 10 | // supports. |
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| 11 | // UNSUPPORTED: gcc |
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| 12 | |
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| 13 | // High parallelism increases our chances of detecting a lack of atomicity. |
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| 14 | #define NUM_THREADS_TRY 256 |
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| 15 | |
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| 16 | #include <limits.h> |
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| 17 | #include <omp.h> |
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| 18 | #include <stdio.h> |
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| 19 | |
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| 20 | int main() { |
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| 21 | // CHECK: signed: num_threads=[[#NUM_THREADS:]]{{$}} |
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| 22 | // CHECK-NEXT: signed: xs=[[#NUM_THREADS-1]]{{$}} |
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| 23 | int xs = -1; |
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| 24 | int numThreads; |
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| 25 | #pragma omp parallel for num_threads(NUM_THREADS_TRY) |
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| 26 | for (int i = 0; i < omp_get_num_threads(); ++i) { |
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| 27 | #pragma omp atomic compare |
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| 28 | if (xs < i) { xs = i; } |
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| 29 | if (i == 0) |
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| 30 | numThreads = omp_get_num_threads(); |
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| 31 | } |
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| 32 | printf(format: "signed: num_threads=%d\n" , numThreads); |
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| 33 | printf(format: "signed: xs=%d\n" , xs); |
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| 34 | |
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| 35 | // CHECK-NEXT: unsigned: xu=0x0{{$}} |
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| 36 | unsigned xu = UINT_MAX; |
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| 37 | #pragma omp parallel for num_threads(NUM_THREADS_TRY) |
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| 38 | for (int i = 0; i < omp_get_num_threads(); ++i) { |
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| 39 | #pragma omp atomic compare |
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| 40 | if (xu > i) { xu = i; } |
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| 41 | } |
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| 42 | printf(format: "unsigned: xu=0x%x\n" , xu); |
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| 43 | return 0; |
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| 44 | } |
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| 45 | |
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