bug#23772: 24.5; (format "%s" INTEGER) is slow

[ynyaaa]

(format "%s" INTEGER) is slower than (format "%s" (format "%d" INTEGER)).

(benchmark-run-compiled 100000 (format "%s" 0))
=>(1.134 12 0.09000000000000119)
(benchmark-run-compiled 100000 (format "%d" 0))
=>(0.571 6 0.05500000000000016)
(benchmark-run-compiled 100000 (format "%s" (format "%d" 0)))
=>(0.652 13 0.12200000000000033)




In GNU Emacs 24.5.1 (i686-pc-mingw32)
 of 2015-04-11 on LEG570
Windowing system distributor `Microsoft Corp.', version 6.0.6002
Configured using:
 `configure --prefix=/c/usr --host=i686-pc-mingw32'

Important settings:
  value of $LANG: JPN
  locale-coding-system: cp932

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils advice help-at-pt misearch multi-isearch info
cus-start cus-load byte-opt bytecomp byte-compile cl-extra cl-loaddefs
cl-lib cconv benchmark help-mode easymenu help-fns time-date japan-util
tooltip electric uniquify ediff-hook vc-hooks lisp-float-type mwheel
dos-w32 ls-lisp w32-common-fns disp-table w32-win w32-vars tool-bar dnd
fontset image regexp-opt fringe tabulated-list newcomment lisp-mode
prog-mode register page menu-bar rfn-eshadow timer select scroll-bar
mouse jit-lock font-lock syntax facemenu font-core frame cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev
minibuffer nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
w32notify w32 multi-tty emacs)

Memory information:
((conses 8 100246 4506)
 (symbols 32 19808 0)
 (miscs 32 91 254)
 (strings 16 17110 3554)
 (string-bytes 1 453874)
 (vectors 8 12074)
 (vector-slots 4 483850 2486)
 (floats 8 64 468)
 (intervals 28 1181 16)
 (buffers 508 14))