PR c++/88613 - ICE with use of const var in lambda.

The issue here was that we were cp_folding a location wrapper around a
lambda capture proxy before it had been mark_rvalue_used.  I considered
adding mark_rvalue_use calls to build_new_op_1, but it seems appropriate to
have them in cp_fold_maybe_rvalue when we know we're trying to produce an
rvalue.

The change to mark_use is for a related issue: when we change the operand of
the location wrapper from VAR_DECL to INTEGER_CST, we need the TREE_CODE of
the location wrapper to change as well, from VIEW_CONVERT_EXPR to
NON_LVALUE_EXPR.

	* expr.c (mark_use): Fix location wrapper handling.
	* cp-gimplify.c (cp_fold_maybe_rvalue): Call mark_rvalue_use.

From-SVN: r267859

1 files changed, 15 insertions, 2 deletions

diff --git a/gcc/cp/expr.c b/gcc/cp/expr.c
index 071c6fb..9160043 100644
--- a/gcc/cp/expr.c
+++ b/gcc/cp/expr.c
@@ -187,10 +187,23 @@ mark_use (tree expr, bool rvalue_p, bool read_p,
 	}
       break;
 
-    CASE_CONVERT:
     case VIEW_CONVERT_EXPR:
       if (location_wrapper_p (expr))
-	loc = EXPR_LOCATION (expr);
+	{
+	  loc = EXPR_LOCATION (expr);
+	  tree op = TREE_OPERAND (expr, 0);
+	  tree nop = RECUR (op);
+	  if (nop == error_mark_node)
+	    return error_mark_node;
+	  TREE_OPERAND (expr, 0) = nop;
+	  /* If we're replacing a DECL with a constant, we also need to change
+	     the TREE_CODE of the location wrapper.  */
+	  if (op != nop && rvalue_p)
+	    TREE_SET_CODE (expr, NON_LVALUE_EXPR);
+	  return expr;
+	}
+      gcc_fallthrough();
+    CASE_CONVERT:
       recurse_op[0] = true;
       break;