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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/95076] Failure to tail-call on function call of different return type Date: Tue, 12 May 2020 12:02:37 +0000 [thread overview] Message-ID: <bug-95076-4-155jcopwfT@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-95076-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95076 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Summary|Failure to optimize out |Failure to tail-call on |stack alignment on function |function call of different |call of different type on |return type |x86 | CC| |hjl.tools at gmail dot com Target| |x86_64-*-* i?86-*-* --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- GCC doesn't tail-call because the return types are not compatible. With a call it cannot optimize the stack adjustment because of the ABI. Note I'm not sure whether the ABI allows %rax to contain "garbage" in the upper half for a function returning in %eax. So what LLVM does may be wrong.
next prev parent reply other threads:[~2020-05-12 12:02 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-05-12 7:47 [Bug target/95076] New: Failure to optimize out stack alignment on function call of different type gabravier at gmail dot com 2020-05-12 12:02 ` rguenth at gcc dot gnu.org [this message] 2020-05-12 13:13 ` [Bug target/95076] Failure to tail-call on function call of different return type hjl.tools at gmail dot com 2020-05-12 13:13 ` hjl.tools at gmail dot com 2020-05-12 13:15 ` hjl.tools at gmail dot com 2020-05-12 13:24 ` jakub at gcc dot gnu.org 2021-04-27 11:38 ` jakub at gcc dot gnu.org 2021-07-28 7:04 ` rguenth at gcc dot gnu.org
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