[gcc r15-6658] Only apply adjust_args in OpenMP dispatch if variant substitution occurs

[Paul-Antoine Arras via Gcc-cvs]

https://gcc.gnu.org/g:aa688dd6302fd9fd4a6ede232bbe63781e672ae9

commit r15-6658-gaa688dd6302fd9fd4a6ede232bbe63781e672ae9
Author: Paul-Antoine Arras <par...@baylibre.com>
Date:   Mon Jan 6 17:00:10 2025 +0100

    Only apply adjust_args in OpenMP dispatch if variant substitution occurs
    
    This is a followup to
    084ea8ad584 OpenMP: middle-end support for dispatch + adjust_args.
    
    This patch fixes a bug that caused arguments in an OpenMP dispatch call to 
be
    modified even when no variant substitution occurred.
    
    gcc/ChangeLog:
    
            * gimplify.cc (gimplify_call_expr): Create variable
            variant_substituted_p to control whether adjust_args applies.
    
    gcc/testsuite/ChangeLog:
    
            * c-c++-common/gomp/adjust-args-4.c: New test.

Diff:
---
 gcc/gimplify.cc                                 | 13 +++++++++----
 gcc/testsuite/c-c++-common/gomp/adjust-args-4.c | 24 ++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index bd324be926ae..251d581f44cd 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -3857,7 +3857,8 @@ gimplify_call_expr (tree *expr_p, gimple_seq *pre_p, bool 
want_value)
   enum gimplify_status ret;
   int i, nargs;
   gcall *call;
-  bool builtin_va_start_p = false, omp_dispatch_p = false;
+  bool builtin_va_start_p = false, omp_dispatch_p = false,
+       variant_substituted_p = false;
   location_t loc = EXPR_LOCATION (*expr_p);
 
   gcc_assert (TREE_CODE (*expr_p) == CALL_EXPR);
@@ -4035,7 +4036,10 @@ gimplify_call_expr (tree *expr_p, gimple_seq *pre_p, 
bool want_value)
     {
       tree variant = omp_resolve_declare_variant (fndecl);
       if (variant != fndecl)
-       CALL_EXPR_FN (*expr_p) = build1 (ADDR_EXPR, fnptrtype, variant);
+       {
+         CALL_EXPR_FN (*expr_p) = build1 (ADDR_EXPR, fnptrtype, variant);
+         variant_substituted_p = true;
+       }
     }
 
   /* There is a sequence point before the call, so any side effects in
@@ -4325,8 +4329,9 @@ gimplify_call_expr (tree *expr_p, gimple_seq *pre_p, bool 
want_value)
                                }
                            }
 
-                         if ((need_device_ptr && !is_device_ptr)
-                             || (need_device_addr && !has_device_addr))
+                         if (variant_substituted_p
+                             && ((need_device_ptr && !is_device_ptr)
+                                 || (need_device_addr && !has_device_addr)))
                            {
                              if (dispatch_device_num == NULL_TREE)
                                {
diff --git a/gcc/testsuite/c-c++-common/gomp/adjust-args-4.c 
b/gcc/testsuite/c-c++-common/gomp/adjust-args-4.c
new file mode 100644
index 000000000000..377932e1b9cc
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/gomp/adjust-args-4.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-fdump-tree-gimple" } */
+
+/* Ensure that adjust_args is only applied when variant substitution happens. 
*/
+
+void h(int *);
+void f(int *);
+#pragma omp declare variant(f) match(construct={dispatch}) 
adjust_args(need_device_ptr : x)
+void g(int *x);
+
+void foo(int *y)
+{
+  #pragma omp dispatch
+    h(y);
+  #pragma omp dispatch
+    f(y);
+  #pragma omp dispatch
+    g(y);
+}
+
+/* { dg-final { scan-tree-dump-times "h \\(y\\);" 1 "gimple" } } */
+/* { dg-final { scan-tree-dump-times "f \\(y\\);" 1 "gimple" } } */
+/* { dg-final { scan-tree-dump-times "D\.\[0-9]+ = 
__builtin_omp_get_mapped_ptr \\(y, D\.\[0-9]+\\);" 1 "gimple" } } */
+/* { dg-final { scan-tree-dump-times "f \\(D\.\[0-9]+\\);" 1 "gimple" } } */