[PATCH] i386: More use reference of struct ix86_frame to avoid copy

[H.J. Lu]

This patch has been used with my Spectre backport for GCC 7 for many
weeks and has been checked into GCC 7 branch.  Should I revert it on
GCC 7 branch or check it into trunk?

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

        * config/i386/i386.c (ix86_expand_prologue): Use reference of
        struct ix86_frame.
        (ix86_expand_epilogue): Likewise.
---
 gcc/config/i386/i386.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index bfb31db8752..9eba3ffd5d6 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -13385,7 +13385,6 @@ ix86_expand_prologue (void)
 {
   struct machine_function *m = cfun->machine;
   rtx insn, t;
-  struct ix86_frame frame;
   HOST_WIDE_INT allocate;
   bool int_registers_saved;
   bool sse_registers_saved;
@@ -13413,7 +13412,7 @@ ix86_expand_prologue (void)
   m->fs.sp_valid = true;
   m->fs.sp_realigned = false;
 
-  frame = m->frame;
+  struct ix86_frame &frame = cfun->machine->frame;
 
   if (!TARGET_64BIT && ix86_function_ms_hook_prologue (current_function_decl))
     {
@@ -14291,7 +14290,6 @@ ix86_expand_epilogue (int style)
 {
   struct machine_function *m = cfun->machine;
   struct machine_frame_state frame_state_save = m->fs;
-  struct ix86_frame frame;
   bool restore_regs_via_mov;
   bool using_drap;
   bool restore_stub_is_tail = false;
@@ -14304,7 +14302,7 @@ ix86_expand_epilogue (int style)
     }
 
   ix86_finalize_stack_frame_flags ();
-  frame = m->frame;
+  struct ix86_frame &frame = cfun->machine->frame;
 
   m->fs.sp_realigned = stack_realign_fp;
   m->fs.sp_valid = stack_realign_fp
-- 
2.14.3