[PATCH 2/3] GCC 7: i386: Use reference of struct ix86_frame to avoid copy

[H.J. Lu]

From: hjl <hjl@138bc75d-0d04-0410-961f-82ee72b054a4>

When there is no need to make a copy of ix86_frame, we can use reference
of struct ix86_frame to avoid copy.

Tested on x86-64.

        Backport from mainline
        * config/i386/i386.c (ix86_can_use_return_insn_p): Use reference
        of struct ix86_frame.
        (ix86_initial_elimination_offset): Likewise.
        (ix86_expand_split_stack_prologue): Likewise.
---
 gcc/config/i386/i386.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 813337242d8..397ef7cac26 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -11843,8 +11843,6 @@ symbolic_reference_mentioned_p (rtx op)
 bool
 ix86_can_use_return_insn_p (void)
 {
-  struct ix86_frame frame;
-
   /* Don't use `ret' instruction in interrupt handler.  */
   if (! reload_completed
       || frame_pointer_needed
@@ -11857,7 +11855,7 @@ ix86_can_use_return_insn_p (void)
     return 0;
 
   ix86_compute_frame_layout ();
-  frame = cfun->machine->frame;
+  struct ix86_frame &frame = cfun->machine->frame;
   return (frame.stack_pointer_offset == UNITS_PER_WORD
          && (frame.nregs + frame.nsseregs) == 0);
 }
@@ -12344,7 +12342,7 @@ HOST_WIDE_INT
 ix86_initial_elimination_offset (int from, int to)
 {
   ix86_compute_frame_layout ();
-  struct ix86_frame frame = cfun->machine->frame;
+  struct ix86_frame &frame = cfun->machine->frame;
 
   if (from == ARG_POINTER_REGNUM && to == HARD_FRAME_POINTER_REGNUM)
     return frame.hard_frame_pointer_offset;
@@ -14860,7 +14858,6 @@ static GTY(()) rtx split_stack_fn_large;
 void
 ix86_expand_split_stack_prologue (void)
 {
-  struct ix86_frame frame;
   HOST_WIDE_INT allocate;
   unsigned HOST_WIDE_INT args_size;
   rtx_code_label *label;
@@ -14873,7 +14870,7 @@ ix86_expand_split_stack_prologue (void)
 
   ix86_finalize_stack_realign_flags ();
   ix86_compute_frame_layout ();
-  frame = cfun->machine->frame;
+  struct ix86_frame &frame = cfun->machine->frame;
   allocate = frame.stack_pointer_offset - INCOMING_FRAME_SP_OFFSET;
 
   /* This is the label we will branch to if we have enough stack
-- 
2.14.3