https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101899
Bug ID: 101899
Summary: [OpenMP] Wrong results with !$omp taskloop – but only
in Fortran version
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Keywords: openmp, wrong-code
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: burnus at gcc dot gnu.org
CC: jakub at gcc dot gnu.org
Target Milestone: ---
Created attachment 51300
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51300&action=edit
Testcase – gfortran -fopenmp test.f90
This is based on the Fortranized testcase of
libgomp/testsuite/libgomp.c-c++-common/masked-1.c
The result for the program in this PR is the same with GCC 10, 11 and current
mainline.
With 'omp taskloop' commented, the program fills
the array 'a' with [0, 1, ..., 127].
However, with 'omp taskloop', the final result is '0' for all array elements.
Looking at the output of
a(i) = a(i) + i
print *, i, a(i), omp_get_thread_num ()
in the taskloop shows:
123 123 0
124 124 0
125 125 0
126 126 0
127 127 0
64 64 2
65 65 2
...
76 76 2
0 0 1
1 1 1
2 2 1
Thus, inside the loop, it is correctly set – but after the taskloop (also
inside 'omp master'), a(:) == 0.
