From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id F14313858C3A; Fri, 29 Mar 2024 12:58:11 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org F14313858C3A
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1711717091;
	bh=hJsgTPfHzCVANvIL3SGkTdWZOvbBheMHFEvmxGKvIbk=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=e3pHj0KM03NsrxgoNj4LxvgxLRwdJQEkofhfC6N8SemdpbL6HfmlDc/nIoMB+j6iw
	 iY+3CPjHhbFnXMI7I6oCqiF4CbpEqpEglv2pe6Iohf6zzOa/cXF/GEZ2pswEMxPUfK
	 j6FrgHNSRThNaTuIj0BJeez+5VAL0gxgSdQ2Hdhw=
From: "segher at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/113652] [14 regression] Failed bootstrap on ppc
 unrecognized opcode: `lfiwzx' with -mcpu=7450
Date: Fri, 29 Mar 2024 12:58:09 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: target
X-Bugzilla-Version: 14.0
X-Bugzilla-Keywords: assemble-failure, build
X-Bugzilla-Severity: normal
X-Bugzilla-Who: segher at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: segher at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 14.0
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-113652-4-NsdRM9onb3@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-113652-4@http.gcc.gnu.org/bugzilla/>
References: <bug-113652-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113652

--- Comment #20 from Segher Boessenkool <segher at gcc dot gnu.org> ---
(In reply to Michael Meissner from comment #19)
> When I wrote the VSX support many years ago, I intended that -mvsx enable
> all of ISA 2.06

But that is not how we do things, and it can never work predictably and
reliably.

If you want ISA 2.07 you have to use -mcpu=3Dpower8, or any other CPU that
implements that ISA level.  Using other options is counterintuitive, confus=
ing,
and causes problems directly even.

> The reason is the kernel needs to
> be built without floating point support.

The kernel and many other things.  That's what -msoft-float, -mno-altivec, =
and
-mno-vsx are for.  Those options mean use no FPRs, no VRs, or no VSRs.  Not=
hing
more, nothing less.=20=20

> If you say -mvsx, it should include the standard power7 integer instructi=
ons
> (-mpopcntd), power6 server instructions (i.e. -mhard-dfp, -mcmpb, -mrecip,
> -mpowerpc-gfxopt, and -mpowerpc-gpopt), etc.

No.  -mvsx means the compiler can use VSX things, is not prevented from it =
by
-mno-vsx.  There can be other reasons it can not use VSX, like, the targeted
CPU does not support VSX.

The option says absolutely nothing about any other instructions.

> VSX support assumes it can use lfiwax and lfiwzx.

Any CPU that supports VSX is ISA 2.07 at least, yes.=