tcg/optimize: rework copy progagation

The copy propagation pass tries to keep track what is a copy of what
and what has copy of what, and in addition it keep a circular list of
of all the copies. Unfortunately this doesn't fully work: a mov from
a temp which has a state "COPY" changed it into a state "HAS_COPY".
Later when this temp is used again, it is considered has not having
copy and thus no propagation is done.

This patch fixes that by removing the hiearchy between copies, and thus
only keeping a "COPY" state both meaning "is a copy" and "has a copy".
The decision of which copy to use is deferred to the actual temp
replacement. At this stage there is not one best choice to do, but only
better choices than others. For doing the best choice the operation
would have to be parsed in reversed to know if a temp is going to be
used later or not. That what is done by the liveness analysis. At this
stage it is known that globals will be always live, that local temps
will be dead at the end of the translation block, and that the temps
will be dead at the end of the basic block. This means that this stage
should try to replace temps by local temps or globals and local temps
by globals.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
1 file changed
tree: 0d5439a680e4fbb3524c9ae1cac6309943fe9314
  1. audio/
  2. block/
  3. bsd-user/
  4. default-configs/
  5. docs/
  6. fpu/
  7. fsdev/
  8. gdb-xml/
  9. hw/
  10. include/
  11. libcacard/
  12. linux-headers/
  13. linux-user/
  14. net/
  15. pc-bios/
  16. qapi/
  17. qga/
  18. QMP/
  19. qom/
  20. roms/
  21. scripts/
  22. slirp/
  23. sysconfigs/
  24. target-alpha/
  25. target-arm/
  26. target-cris/
  27. target-i386/
  28. target-lm32/
  29. target-m68k/
  30. target-microblaze/
  31. target-mips/
  32. target-openrisc/
  33. target-ppc/
  34. target-s390x/
  35. target-sh4/
  36. target-sparc/
  37. target-unicore32/
  38. target-xtensa/
  39. tcg/
  40. tests/
  41. trace/
  42. ui/
  43. .exrc
  44. .gitignore
  45. .gitmodules
  46. .mailmap
  47. a.out.h
  48. acl.c
  49. acl.h
  50. aes.c
  51. aes.h
  52. aio.c
  53. alpha-dis.c
  54. alpha.ld
  55. arch_init.c
  56. arch_init.h
  57. arm-dis.c
  58. arm.ld
  59. async.c
  60. balloon.c
  61. balloon.h
  62. bitmap.c
  63. bitmap.h
  64. bitops.c
  65. bitops.h
  66. block-migration.c
  67. block-migration.h
  68. block.c
  69. block.h
  70. block_int.h
  71. blockdev.c
  72. blockdev.h
  73. bswap.h
  74. bt-host.c
  75. bt-host.h
  76. bt-vhci.c
  77. buffered_file.c
  78. buffered_file.h
  79. cache-utils.c
  80. cache-utils.h
  81. Changelog
  82. cmd.c
  83. cmd.h
  84. CODING_STYLE
  85. compatfd.c
  86. compatfd.h
  87. compiler.h
  88. config.h
  89. configure
  90. console.c
  91. console.h
  92. COPYING
  93. COPYING.LIB
  94. coroutine-gthread.c
  95. coroutine-sigaltstack.c
  96. coroutine-ucontext.c
  97. coroutine-win32.c
  98. cpu-all.h
  99. cpu-common.h
  100. cpu-defs.h
  101. cpu-exec.c
  102. cpus.c
  103. cpus.h
  104. cputlb.c
  105. cputlb.h
  106. cris-dis.c
  107. cursor.c
  108. cursor_hidden.xpm
  109. cursor_left_ptr.xpm
  110. cutils.c
  111. def-helper.h
  112. device_tree.c
  113. device_tree.h
  114. dis-asm.h
  115. disas.c
  116. disas.h
  117. dma-helpers.c
  118. dma.h
  119. dump-stub.c
  120. dump.c
  121. dump.h
  122. elf.h
  123. envlist.c
  124. envlist.h
  125. error.c
  126. error.h
  127. event_notifier.c
  128. event_notifier.h
  129. exec-all.h
  130. exec-memory.h
  131. exec-obsolete.h
  132. exec.c
  133. gdbstub.c
  134. gdbstub.h
  135. gen-icount.h
  136. HACKING
  137. hmp-commands.hx
  138. hmp.c
  139. hmp.h
  140. host-utils.c
  141. host-utils.h
  142. hppa-dis.c
  143. hppa.ld
  144. i386-dis.c
  145. i386.ld
  146. ia64-dis.c
  147. ia64.ld
  148. input.c
  149. int128.h
  150. iohandler.c
  151. ioport.c
  152. ioport.h
  153. iorange.h
  154. iov.c
  155. iov.h
  156. json-lexer.c
  157. json-lexer.h
  158. json-parser.c
  159. json-parser.h
  160. json-streamer.c
  161. json-streamer.h
  162. kvm-all.c
  163. kvm-stub.c
  164. kvm.h
  165. libfdt_env.h
  166. LICENSE
  167. linux-aio.c
  168. lm32-dis.c
  169. m68k-dis.c
  170. m68k.ld
  171. main-loop.c
  172. main-loop.h
  173. MAINTAINERS
  174. Makefile
  175. Makefile.dis
  176. Makefile.hw
  177. Makefile.objs
  178. Makefile.target
  179. Makefile.user
  180. memory.c
  181. memory.h
  182. memory_mapping-stub.c
  183. memory_mapping.c
  184. memory_mapping.h
  185. microblaze-dis.c
  186. migration-exec.c
  187. migration-fd.c
  188. migration-tcp.c
  189. migration-unix.c
  190. migration.c
  191. migration.h
  192. mips-dis.c
  193. mips.ld
  194. module.c
  195. module.h
  196. monitor.c
  197. monitor.h
  198. nbd.c
  199. nbd.h
  200. net.c
  201. net.h
  202. notify.c
  203. notify.h
  204. os-posix.c
  205. os-win32.c
  206. osdep.c
  207. osdep.h
  208. oslib-posix.c
  209. oslib-win32.c
  210. page_cache.c
  211. path.c
  212. pci-ids.txt
  213. pflib.c
  214. pflib.h
  215. poison.h
  216. posix-aio-compat.c
  217. ppc-dis.c
  218. ppc.ld
  219. ppc64.ld
  220. qapi-schema-guest.json
  221. qapi-schema-test.json
  222. qapi-schema.json
  223. qbool.c
  224. qbool.h
  225. qdict-test-data.txt
  226. qdict.c
  227. qdict.h
  228. qemu-aio.h
  229. qemu-barrier.h
  230. qemu-bridge-helper.c
  231. qemu-char.c
  232. qemu-char.h
  233. qemu-common.h
  234. qemu-config.c
  235. qemu-config.h
  236. qemu-coroutine-int.h
  237. qemu-coroutine-io.c
  238. qemu-coroutine-lock.c
  239. qemu-coroutine-sleep.c
  240. qemu-coroutine.c
  241. qemu-coroutine.h
  242. qemu-doc.texi
  243. qemu-error.c
  244. qemu-error.h
  245. qemu-file.h
  246. qemu-ga.c
  247. qemu-img-cmds.hx
  248. qemu-img.c
  249. qemu-img.texi
  250. qemu-io.c
  251. qemu-lock.h
  252. qemu-log.c
  253. qemu-log.h
  254. qemu-nbd.c
  255. qemu-nbd.texi
  256. qemu-objects.h
  257. qemu-option-internal.h
  258. qemu-option.c
  259. qemu-option.h
  260. qemu-options-wrapper.h
  261. qemu-options.h
  262. qemu-options.hx
  263. qemu-os-posix.h
  264. qemu-os-win32.h
  265. qemu-progress.c
  266. qemu-queue.h
  267. qemu-seccomp.c
  268. qemu-seccomp.h
  269. qemu-sockets.c
  270. qemu-tech.texi
  271. qemu-thread-posix.c
  272. qemu-thread-posix.h
  273. qemu-thread-win32.c
  274. qemu-thread-win32.h
  275. qemu-thread.h
  276. qemu-timer-common.c
  277. qemu-timer.c
  278. qemu-timer.h
  279. qemu-tls.h
  280. qemu-tool.c
  281. qemu-user.c
  282. qemu-x509.h
  283. qemu-xattr.h
  284. qemu.sasl
  285. qemu_socket.h
  286. qerror.c
  287. qerror.h
  288. qfloat.c
  289. qfloat.h
  290. qint.c
  291. qint.h
  292. qjson.c
  293. qjson.h
  294. qlist.c
  295. qlist.h
  296. qmp-commands.hx
  297. qmp.c
  298. qobject.h
  299. qstring.c
  300. qstring.h
  301. qtest.c
  302. qtest.h
  303. range.h
  304. readline.c
  305. readline.h
  306. README
  307. rules.mak
  308. s390-dis.c
  309. s390.ld
  310. savevm.c
  311. sh4-dis.c
  312. softmmu-semi.h
  313. softmmu_defs.h
  314. softmmu_exec.h
  315. softmmu_header.h
  316. softmmu_template.h
  317. sparc-dis.c
  318. sparc.ld
  319. sparc64.ld
  320. spice-qemu-char.c
  321. sysemu.h
  322. targphys.h
  323. tcg-runtime.c
  324. tci-dis.c
  325. tci.c
  326. thunk.c
  327. thunk.h
  328. TODO
  329. trace-events
  330. translate-all.c
  331. uboot_image.h
  332. user-exec.c
  333. VERSION
  334. version.rc
  335. vgafont.h
  336. vl.c
  337. vmstate.h
  338. x86_64.ld
  339. xen-all.c
  340. xen-mapcache.c
  341. xen-mapcache.h
  342. xen-stub.c