[Bug c++/123597] [14/15/16 Regression][OpenMP] Local variable wrongly hoisted (and shared) with templates and collapse(2)

[jakub at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123597

--- Comment #14 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So, I'd go with at least
--- gcc/cp/parser.cc.jj 2026-01-21 14:23:48.925730642 +0100
+++ gcc/cp/parser.cc    2026-01-22 15:34:08.691354819 +0100
@@ -49853,6 +49853,9 @@ substitute_in_tree_walker (tree *tp, int
   else if (TREE_CODE (*tp) == BIND_EXPR
           && BIND_EXPR_BODY (*tp) == sit->orig
           && !BIND_EXPR_VARS (*tp)
+          /* BIND_EXPRs in templates likely have NULL BIND_EXPR_VARS,
+             are created by begin_compound_stmt and are not redundant.  */
+          && !processing_template_decl
           && (sit->flatten || TREE_CODE (sit->repl) == BIND_EXPR))
     {
       *tp = sit->repl;
@@ -49897,7 +49900,12 @@ substitute_in_tree (tree *context, tree
   struct sit_data data;

   gcc_assert (*context && orig && repl);
-  if (TREE_CODE (repl) == BIND_EXPR && !BIND_EXPR_VARS (repl))
+  /* Look through redundant BIND_EXPR.  BIND_EXPRs in templates likely have
+     NULL BIND_EXPR_VARS, are created by begin_compound_stmt and are not
+     redundant.  */
+  if (TREE_CODE (repl) == BIND_EXPR
+      && !BIND_EXPR_VARS (repl)
+      && !processing_template_decl)
     repl = BIND_EXPR_BODY (repl);
   data.orig = orig;
   data.repl = repl;