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From: "dimitri.gorokhovik at free dot fr" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/109903] Register misallocation in hand-crafted asm insn, no diagnostics produced
Date: Thu, 18 May 2023 15:28:46 +0000	[thread overview]
Message-ID: <bug-109903-4-Oy2BwIj8P6@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-109903-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109903

--- Comment #4 from Dimitri Gorokhovik <dimitri.gorokhovik at free dot fr> ---
Hi Andrew,

I'd agree more with "WONTFIX" here ;-) We are not looking for solution. We want
to spare the same hassle to others.

This asm doesn't write to memory, it doesn't even read any -- 'a' is passed
over in the registers with aarch64 and x64_86.

It is also very hard to see the need for early clobber here ... how comes the
version with return value doesn't need it while the other does? The asm
performs regular register loads. Certainly we are not marking all register
loads with early clobbers are we?

WE ended up moving 'a' to output clause, it feels barely more contorted than
the early-clobber method.

> GCC does not look at the inline-asm template except while outputting the assembly.
Yep, reason why I let it emit ARMv8 insns for the x64_86 target ;-)

  parent reply	other threads:[~2023-05-18 15:28 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-18 14:59 [Bug target/109903] New: " dimitri.gorokhovik at free dot fr
2023-05-18 15:02 ` [Bug target/109903] " pinskia at gcc dot gnu.org
2023-05-18 15:04 ` pinskia at gcc dot gnu.org
2023-05-18 15:05 ` pinskia at gcc dot gnu.org
2023-05-18 15:28 ` dimitri.gorokhovik at free dot fr [this message]
2023-05-18 15:50 ` pinskia at gcc dot gnu.org
2023-05-18 16:09 ` dimitri.gorokhovik at free dot fr

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