[PATCH] i386: Use const reference of struct ix86_frame to avoid copy

[H.J. Lu]

We can use const reference of struct ix86_frame to avoid making a local
copy of ix86_frame.  ix86_expand_epilogue makes a local copy of struct
ix86_frame and uses the reg_save_offset field as a local variable.  This
patch uses a separate local variable for reg_save_offset.

Tested on x86-64 with ada.  OK for trunk?

H.J.
--
        PR target/83905
        * config/i386/i386.c (ix86_expand_prologue): Use cost reference
        of struct ix86_frame.
        (ix86_expand_epilogue): Likewise.  Add a local variable for
        the reg_save_offset field in struct ix86_frame.
---
 gcc/config/i386/i386.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index a301e18ed70..340eca42449 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;
+  const 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;
+  const struct ix86_frame &frame = cfun->machine->frame;
 
   m->fs.sp_realigned = stack_realign_fp;
   m->fs.sp_valid = stack_realign_fp
@@ -14348,11 +14346,13 @@ ix86_expand_epilogue (int style)
                                  + UNITS_PER_WORD);
     }
 
+  HOST_WIDE_INT reg_save_offset = frame.reg_save_offset;
+
   /* Special care must be taken for the normal return case of a function
      using eh_return: the eax and edx registers are marked as saved, but
      not restored along this path.  Adjust the save location to match.  */
   if (crtl->calls_eh_return && style != 2)
-    frame.reg_save_offset -= 2 * UNITS_PER_WORD;
+    reg_save_offset -= 2 * UNITS_PER_WORD;
 
   /* EH_RETURN requires the use of moves to function properly.  */
   if (crtl->calls_eh_return)
@@ -14368,11 +14368,11 @@ ix86_expand_epilogue (int style)
   else if (TARGET_EPILOGUE_USING_MOVE
           && cfun->machine->use_fast_prologue_epilogue
           && (frame.nregs > 1
-              || m->fs.sp_offset != frame.reg_save_offset))
+              || m->fs.sp_offset != reg_save_offset))
     restore_regs_via_mov = true;
   else if (frame_pointer_needed
           && !frame.nregs
-          && m->fs.sp_offset != frame.reg_save_offset)
+          && m->fs.sp_offset != reg_save_offset)
     restore_regs_via_mov = true;
   else if (frame_pointer_needed
           && TARGET_USE_LEAVE
@@ -14440,7 +14440,7 @@ ix86_expand_epilogue (int style)
       rtx t;
 
       if (frame.nregs)
-       ix86_emit_restore_regs_using_mov (frame.reg_save_offset, style == 2);
+       ix86_emit_restore_regs_using_mov (reg_save_offset, style == 2);
 
       /* eh_return epilogues need %ecx added to the stack pointer.  */
       if (style == 2)
@@ -14535,19 +14535,19 @@ ix86_expand_epilogue (int style)
         in epilogues.  */
       if (!m->fs.sp_valid || m->fs.sp_realigned
          || (TARGET_SEH
-             && (m->fs.sp_offset - frame.reg_save_offset
+             && (m->fs.sp_offset - reg_save_offset
                  >= SEH_MAX_FRAME_SIZE)))
        {
          pro_epilogue_adjust_stack (stack_pointer_rtx, hard_frame_pointer_rtx,
                                     GEN_INT (m->fs.fp_offset
-                                             - frame.reg_save_offset),
+                                             - reg_save_offset),
                                     style, false);
        }
-      else if (m->fs.sp_offset != frame.reg_save_offset)
+      else if (m->fs.sp_offset != reg_save_offset)
        {
          pro_epilogue_adjust_stack (stack_pointer_rtx, stack_pointer_rtx,
                                     GEN_INT (m->fs.sp_offset
-                                             - frame.reg_save_offset),
+                                             - reg_save_offset),
                                     style,
                                     m->fs.cfa_reg == stack_pointer_rtx);
        }
-- 
2.14.3