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From: "unlvsur at live dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/107167] It looks like GCC wastes registers on trivial computations when result can be cached
Date: Thu, 06 Oct 2022 06:05:50 +0000 [thread overview]
Message-ID: <bug-107167-4-griyeNkEXv@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-107167-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107167
--- Comment #4 from cqwrteur <unlvsur at live dot com> ---
(In reply to Andrew Pinski from comment #1)
> Plus your example might be slower due to dependencies.
Dependency is only an issue to a certain degree. 1st one it has things like
"movl %edi, %edx; rorl $11, %edx" which is also a flow dependency.
CPU solves flow dependency to a very large degree with register forwarding.
Write dependencies are also dealt with register renaming if we save registers,
register renaming will also save time.
next prev parent reply other threads:[~2022-10-06 6:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-06 5:33 [Bug rtl-optimization/107167] New: " unlvsur at live dot com
2022-10-06 5:55 ` [Bug rtl-optimization/107167] " pinskia at gcc dot gnu.org
2022-10-06 6:00 ` unlvsur at live dot com
2022-10-06 6:03 ` unlvsur at live dot com
2022-10-06 6:05 ` unlvsur at live dot com [this message]
2022-10-06 6:47 ` pinskia at gcc dot gnu.org
2022-10-07 1:41 ` unlvsur at live dot com
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