[gcc(refs/users/guojiufu/heads/guojiufu-branch)] c++: Create fewer SAVE_EXPR.

[Jiu Fu Guo]

https://gcc.gnu.org/g:295790712f1168d9d540c240446b167592b77aca

commit 295790712f1168d9d540c240446b167592b77aca
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Jan 14 22:55:59 2020 -0500

    c++: Create fewer SAVE_EXPR.
    
    In a couple of places in build_over_call we were calling
    cp_stabilize_reference but only using the result once, so it isn't needed.
    
    gcc/cp/ChangeLog
    2020-05-18  Jason Merrill  <jason@redhat.com>
    
            * call.c (build_over_call): Remove unnecessary
            cp_stabilize_reference.

Diff:
---
 gcc/cp/ChangeLog | 5 +++++
 gcc/cp/call.c    | 7 +++----
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index e9cd3eb453b..1c4d0657c36 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2020-05-18  Jason Merrill  <jason@redhat.com>
+
+	* call.c (build_over_call): Remove unnecessary
+	cp_stabilize_reference.
+
 2020-05-18  Marek Polacek  <polacek@redhat.com>
 
 	* call.c (add_builtin_candidate): Don't create a builtin overload
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index b96bc06a364..0b0eaa65ad8 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -9003,8 +9003,7 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
       else if ((trivial || TREE_CODE (arg) == TARGET_EXPR)
 	       && !unsafe)
 	{
-	  tree to = cp_stabilize_reference (cp_build_fold_indirect_ref (fa));
-
+	  tree to = cp_build_fold_indirect_ref (fa);
 	  val = build2 (INIT_EXPR, DECL_CONTEXT (fn), to, arg);
 	  return val;
 	}
@@ -9013,8 +9012,7 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
 	   && DECL_OVERLOADED_OPERATOR_IS (fn, NOP_EXPR)
 	   && trivial_fn_p (fn))
     {
-      tree to = cp_stabilize_reference
-	(cp_build_fold_indirect_ref (argarray[0]));
+      tree to = cp_build_fold_indirect_ref (argarray[0]);
       tree type = TREE_TYPE (to);
       tree as_base = CLASSTYPE_AS_BASE (type);
       tree arg = argarray[1];
@@ -9043,6 +9041,7 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
 	  tree array_type, alias_set;
 
 	  arg2 = TYPE_SIZE_UNIT (as_base);
+	  to = cp_stabilize_reference (to);
 	  arg0 = cp_build_addr_expr (to, complain);
 
 	  array_type = build_array_type (unsigned_char_type_node,