[PATCH] regrename: Skip renaming if instruction is noop move.

[Jojo R via Gcc-patches]

Skip renaming if instruction is noop move, and it will
been removed for performance.

gcc/
        * regrename.c (find_rename_reg): Return satisfied regno
        if instruction is noop move.
---
 gcc/regrename.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/gcc/regrename.c b/gcc/regrename.c
index b8a9ca36f22..cb605f5176b 100644
--- a/gcc/regrename.c
+++ b/gcc/regrename.c
@@ -394,6 +394,9 @@ find_rename_reg (du_head_p this_head, enum reg_class 
super_class,
                          this_head, *unavailable))
     return this_head->tied_chain->regno;
 
+  if (noop_move_p (this_head->first->insn))
+    return best_new_reg;
+
   /* If PREFERRED_CLASS is not NO_REGS, we iterate in the first pass
      over registers that belong to PREFERRED_CLASS and try to find the
      best register within the class.  If that failed, we iterate in
-- 
2.24.3 (Apple Git-128)