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From: "hubicka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/106518] Exchange/swap aware register allocation (generate xchg in reload) Date: Thu, 04 Aug 2022 09:53:37 +0000 [thread overview] Message-ID: <bug-106518-4-XjoLCLyoEi@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-106518-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106518 Jan Hubicka <hubicka at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |hubicka at gcc dot gnu.org --- Comment #2 from Jan Hubicka <hubicka at gcc dot gnu.org> --- We have xchg patterns in i386.md and corresponding peephole. I used to play with this long time ago and it was not giving any of performance benefits becuase xchg at that time was not well optimized in CPUs. With regstack the main problem is that RTL after reg-stack is inconsistent since we have no way to explicitly express push/pop operations that renumber the registers. Some years ago I made patch for that https://gcc.gnu.org/pipermail/gcc-patches/1999-November/021921.html Even if you make representation correct register allocation for stack based CPU is quite different from normal registr allocation. These days I would more like to see x87 to silently die.
next prev parent reply other threads:[~2022-08-04 9:53 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-08-03 20:14 [Bug rtl-optimization/106518] New: " roger at nextmovesoftware dot com 2022-08-04 9:32 ` [Bug rtl-optimization/106518] " rguenth at gcc dot gnu.org 2022-08-04 9:53 ` hubicka at gcc dot gnu.org [this message] 2023-04-26 8:11 ` cvs-commit at gcc dot gnu.org
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