[PATCH 5/5] Mapping of components of references to pointers to structs for OpenMP/OpenACC

[Chung-Lin Tang]

Hi Julian,

On 2021/5/15 5:27 AM, Julian Brown wrote:
> GCC currently raises a parse error for indirect accesses to struct
> members, where the base of the access is a reference to a pointer.
> This patch fixes that case.

> gcc/cp/
> 	* semantics.c (finish_omp_clauses): Handle components of references to
> 	pointers to structs.
> 
> libgomp/
> 	* testsuite/libgomp.oacc-c++/deep-copy-17.C: Update test.

> --- a/gcc/cp/semantics.c
> +++ b/gcc/cp/semantics.c
> @@ -7670,7 +7670,12 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
>   	  if ((ort == C_ORT_ACC || ort == C_ORT_OMP)
>   	      && TREE_CODE (t) == COMPONENT_REF
>   	      && TREE_CODE (TREE_OPERAND (t, 0)) == INDIRECT_REF)
> -	    t = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
> +	    {
> +	      t = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
> +	      /* References to pointers have a double indirection here.  */
> +	      if (TREE_CODE (t) == INDIRECT_REF)
> +		t = TREE_OPERAND (t, 0);
> +	    }
>   	  if (TREE_CODE (t) == COMPONENT_REF
>   	      && ((ort & C_ORT_OMP_DECLARE_SIMD) == C_ORT_OMP
>   		  || ort == C_ORT_ACC)

There is already a large plethora of such modifications in this patch:
"[PATCH, OG10, OpenMP 5.0, committed] Remove array section base-pointer mapping semantics, and other front-end adjustments."
https://gcc.gnu.org/pipermail/gcc-patches/2021-May/570075.html

I am in the process of taking that patch to mainline, so are you sure this is not already handled there?

> diff --git a/libgomp/testsuite/libgomp.oacc-c++/deep-copy-17.C b/libgomp/testsuite/libgomp.oacc-c++/deep-copy-17.C
> index dacbb520f3d..e038e9e3802 100644
> --- a/libgomp/testsuite/libgomp.oacc-c++/deep-copy-17.C
> +++ b/libgomp/testsuite/libgomp.oacc-c++/deep-copy-17.C
> @@ -83,7 +83,7 @@ void strrp (void)
>     a[0] = 8;
>     c[0] = 10;
>     e[0] = 12;
> -  #pragma acc parallel copy(n->a[0:10], n->c[0:10], n->e[0:10])
> +  #pragma acc parallel copy(n->a[0:10], n->b, n->c[0:10], n->d, n->e[0:10])
>     {
>       n->a[0] = n->c[0] + n->e[0];
>     }

This testcase can be added.

Chung-Lin