[Bug target/60520] stack adjustment are not merged anymore

["hjl.tools at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60520

--- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> ---
This change:

diff --git a/gcc/function.c b/gcc/function.c
index a61e475..3b6718f 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -6238,6 +6238,7 @@ thread_prologue_and_epilogue_insns (void)
         }
       /* Now duplicate the tails.  */
       if (!bitmap_empty_p (&bb_tail))
+        {
         FOR_EACH_BB_REVERSE_FN (bb, cfun)
           {
         basic_block copy_bb, tbb;
@@ -6304,6 +6305,17 @@ thread_prologue_and_epilogue_insns (void)
         if (bitmap_empty_p (&bb_tail))
           break;
           }
+
+        /* Basic blocks may have been changed.  Merge each basic block
+           with its successor if possible.  */
+        FOR_EACH_BB_FN (bb, cfun)
+          if (single_succ_p (bb))
+        {
+          basic_block succ_bb = single_succ (bb);
+          if (can_merge_blocks_p (bb, succ_bb))
+            merge_blocks (bb, succ_bb);
+        }
+        }
     }

     fail_shrinkwrap:

seems to work.