[gcc(refs/users/guojiufu/heads/personal-branch)] coroutines: Fix unused value found by static analysis.

[gcc(refs/users/guojiufu/heads/personal-branch)] coroutines: Fix unused value found by static analysis.

[Jiu Fu Guo]

https://gcc.gnu.org/g:9df0ff5f219b9e93d007f42939a6449ce2521cf5

commit 9df0ff5f219b9e93d007f42939a6449ce2521cf5
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Sat May 30 17:03:40 2020 +0100

    coroutines: Fix unused value found by static analysis.
    
    This fixes up the zero-initialization of the coro frame pointer
    to avoid an unused assigned value, spotted by Martin Liska with
    static analysis.
    
    gcc/cp/ChangeLog:
    
            * coroutines.cc (morph_fn_to_coro): Revise initialization
            of the frame pointer to avoid an unused value.

Diff:
---
 gcc/cp/coroutines.cc | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
index b79e2c66b70..c4df488ac02 100644
--- a/gcc/cp/coroutines.cc
+++ b/gcc/cp/coroutines.cc
@@ -3889,11 +3889,9 @@ morph_fn_to_coro (tree orig, tree *resumer, tree *destroyer)
   /* The decl_expr for the coro frame pointer, initialize to zero so that we
      can pass it to the IFN_CO_FRAME (since there's no way to pass a type,
      directly apparently).  This avoids a "used uninitialized" warning.  */
-  tree r = build_stmt (fn_start, DECL_EXPR, coro_fp);
   tree zeroinit = build1 (CONVERT_EXPR, coro_frame_ptr, integer_zero_node);
-  r = build2 (INIT_EXPR, TREE_TYPE (coro_fp), coro_fp, zeroinit);
-  r = coro_build_cvt_void_expr_stmt (r, fn_start);
-  add_stmt (r);
+  DECL_INITIAL (coro_fp) = zeroinit;
+  add_decl_expr (coro_fp);
 
   /* The CO_FRAME internal function is a mechanism to allow the middle end
      to adjust the allocation in response to optimisations.  We provide the
@@ -4047,7 +4045,7 @@ morph_fn_to_coro (tree orig, tree *resumer, tree *destroyer)
     }
 
   tree allocated = build1 (CONVERT_EXPR, coro_frame_ptr, new_fn);
-  r = build2 (INIT_EXPR, TREE_TYPE (coro_fp), coro_fp, allocated);
+  tree r = build2 (INIT_EXPR, TREE_TYPE (coro_fp), coro_fp, allocated);
   r = coro_build_cvt_void_expr_stmt (r, fn_start);
   add_stmt (r);