Re: C++ PATCH for c++/84036, ICE with variadic lambda capture

[Jason Merrill <jason@redhat.com>]

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On Sun, Feb 11, 2018 at 8:21 PM, Jason Merrill <jason@redhat.com> wrote:
> The old lambda model handled variadic capture by focusing on the
> FIELD_DECL rather than trying to map between capture proxies.  The new
> model relies more on capture proxies, so it makes sense to use them
> more for variadic capture as well.  So with this patch we treat a
> variadic capture proxy as a pack, rather than the field.

Which makes the recently added is_capture_proxy_with_ref redundant.

Tested x86_64-pc-linux-gnu, applying to trunk.

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commit 4f59367cbb4fe82c68f9df30e49af8a2a19dd6cf
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Mar 6 17:31:44 2018 -0500

            * lambda.c (is_capture_proxy_with_ref): Remove.
    
            * constexpr.c, expr.c, cp-tree.h, semantics.c: Adjust.

diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index bd53bfbfe47..2c5a71f3ee5 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -5429,7 +5429,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now,
     case VAR_DECL:
       if (DECL_HAS_VALUE_EXPR_P (t))
 	{
-	  if (now && is_capture_proxy_with_ref (t))
+	  if (now && is_normal_capture_proxy (t))
 	    {
 	      /* -- in a lambda-expression, a reference to this or to a
 		 variable with automatic storage duration defined outside that
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 8f3ec86e8ce..3a6f8f33e8d 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6896,7 +6896,6 @@ extern void insert_capture_proxy		(tree);
 extern void insert_pending_capture_proxies	(void);
 extern bool is_capture_proxy			(tree);
 extern bool is_normal_capture_proxy             (tree);
-extern bool is_capture_proxy_with_ref           (tree);
 extern void register_capture_members		(tree);
 extern tree lambda_expr_this_capture            (tree, bool);
 extern void maybe_generic_this_capture		(tree, tree);
diff --git a/gcc/cp/expr.c b/gcc/cp/expr.c
index b2c8cfaf88c..2e679868970 100644
--- a/gcc/cp/expr.c
+++ b/gcc/cp/expr.c
@@ -111,7 +111,7 @@ mark_use (tree expr, bool rvalue_p, bool read_p,
     {
     case VAR_DECL:
     case PARM_DECL:
-      if (rvalue_p && is_capture_proxy_with_ref (expr))
+      if (rvalue_p && is_normal_capture_proxy (expr))
 	{
 	  /* Look through capture by copy.  */
 	  tree cap = DECL_CAPTURED_VARIABLE (expr);
@@ -154,7 +154,7 @@ mark_use (tree expr, bool rvalue_p, bool read_p,
 	{
 	  /* Try to look through the reference.  */
 	  tree ref = TREE_OPERAND (expr, 0);
-	  if (rvalue_p && is_capture_proxy_with_ref (ref))
+	  if (rvalue_p && is_normal_capture_proxy (ref))
 	    {
 	      /* Look through capture by reference.  */
 	      tree cap = DECL_CAPTURED_VARIABLE (ref);
diff --git a/gcc/cp/lambda.c b/gcc/cp/lambda.c
index 345b210e89c..094979e81a3 100644
--- a/gcc/cp/lambda.c
+++ b/gcc/cp/lambda.c
@@ -291,24 +291,13 @@ is_normal_capture_proxy (tree decl)
   return DECL_NORMAL_CAPTURE_P (val);
 }
 
-/* Returns true iff DECL is a capture proxy for which we can use
-   DECL_CAPTURED_VARIABLE.  In effect, this is a normal proxy other than a
-   nested capture of a function parameter pack.  */
-
-bool
-is_capture_proxy_with_ref (tree var)
-{
-  return (is_normal_capture_proxy (var) && DECL_LANG_SPECIFIC (var)
-	  && DECL_CAPTURED_VARIABLE (var));
-}
-
 /* VAR is a capture proxy created by build_capture_proxy; add it to the
    current function, which is the operator() for the appropriate lambda.  */
 
 void
 insert_capture_proxy (tree var)
 {
-  if (is_capture_proxy_with_ref (var))
+  if (is_normal_capture_proxy (var))
     {
       tree cap = DECL_CAPTURED_VARIABLE (var);
       if (CHECKING_P)
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 8a0096ddf92..bb8b5953539 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -3332,7 +3332,7 @@ process_outer_var_ref (tree decl, tsubst_flags_t complain, bool odr_use)
     {
       /* Check whether we've already built a proxy.  */
       tree var = decl;
-      while (is_capture_proxy_with_ref (var))
+      while (is_normal_capture_proxy (var))
 	var = DECL_CAPTURED_VARIABLE (var);
       tree d = retrieve_local_specialization (var);