Re: [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