I have a question about the item #4 about the Verify_MP_Lowered. I don't
think it's a good fix to remove the verifier. The root issue is there is
only one verifier and the pointer is passed so that it can not be used
recursively.
2010/8/31 Jiangzhou HE <hejiangz...@gmail.com>
> Hi, all,
>
> This is the fixes for several OpenMP bugs. Could gatekeeper help to review
> it? I attached the test case for the fix.
>
> I have fixed the following bugs:
>
> 1. bug of driver (see test_has_openmp.c)
> The case works with -mp but fails with -fopenmp. Since the command line
> options should be compatible with gcc, -fopenmp should also work.
> I fixed this bug by change osprey/driver/OPTION.
>
> 2. bug of atomic directive (see test_atomic.c)
> Atomic directive did not work correctly sometimes.
> Without this fix, atomic directive was lowered to
> INTRN_COMPARE_AND_SWAP_XX. The lowered code checks whether its result is
> non-zero, to decide whether to try again. So INTRN_COMPARE_AND_SWAP_XX
> should be replaced by INTRN_BOOL_COMPARE_AND_SWAP in the lowered code.
> The change for omp_lower.cxx is for this bug.
>
> 3. bug of variable declared in nested block (see test_local_var.c)
>
> For code like this:
>
> int s;
> #pragma parallel
> {
> int t;
> ....
> }
>
> In the parallel region, the variable s should be shared by default, and
> the variable t should be private. However, in WHIRL, all the local variables
> are put in the symbol table of current function, so the declaring block for
> local variables such as s and t cannot be distinguished. Therefore, in the
> backend, both s and t are treated as shared variable, which is not correct.
> I fixed this bug by adding some code in wgen. By this fix, wgen will
> insert an explicit private pragma for local variables such as t.
>
> 4. bug of nested OpenMP directives (see test_nested_critical.c)
>
> Some OpenMP directives, like critical, master, can be nested with each
> other.
>
> Most OpenMP directives are lowered by lower_mp() (in
> osprey/be/com/wn_mp.cxx). lower_mp() is called by lower_block() (in
> osprey/be/com/wn_lower.cxx). lower_mp() returns the first statement of the
> replacing block, so lower_block() will call lower_mp() again for the nested
> directives. I believe that is the right way to deal with the nested OpenMP
> directives ( another way may be run lower_mp() recursively, however, since
> lower_mp() uses many global variables, I think it was not designed to be
> called recursively).
>
> However, there is a class Verify_MP_Lowered in wn_mp.cxx to check
> whether all the generated code in lower_mp() has not OpenMP directives.
> Since for nested OpenMP directives, the generated code in the first
> invocation of lower_mp() would certainly contain OpenMP directives (which
> will be lowered in the next invocation of lower_mp()), I think we should
> remove that verifier here. Most changes of wn_mp.cxx is for that.
>
>
> After applying the fixes, all the cases work.
>
> Thanks.
>
> Regards,
> Jiangzhou
>
> --
> Jiangzhou HE (何江舟)
>
> Institute of High-Performance Computing
> Department of Computer Science and Technology
> Tsinghua University, Beijing, China
>
>
>
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--
Regards,
Lai Jian-Xin
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