From: Paul Koning <paulkoning@comcast.net>
To: Stefan Kanthak <stefan.kanthak@nexgo.de>
Cc: gcc@gnu.org
Subject: Re: Widening multiplication, but no narrowing division [i386/AMD64]
Date: Mon, 9 Jan 2023 09:23:28 -0500 [thread overview]
Message-ID: <A2650E81-2627-4F3C-A531-1D4944C338AB@comcast.net> (raw)
In-Reply-To: <554A1354252F43BB8915A74129C41BE3@H270>
> On Jan 9, 2023, at 7:20 AM, Stefan Kanthak <stefan.kanthak@nexgo.de> wrote:
>
> Hi,
>
> GCC (and other C compilers too) support the widening multiplication
> of i386/AMD64 processors, but DON'T support their narrowing division:
I wonder if this changed in the recent past. I have a pattern for this type of thing in pdp11.md:
(define_expand "divmodhi4"
[(parallel
[(set (subreg:HI (match_dup 1) 0)
(div:HI (match_operand:SI 1 "register_operand" "0")
(match_operand:HI 2 "general_operand" "g")))
(set (subreg:HI (match_dup 1) 2)
(mod:HI (match_dup 1) (match_dup 2)))])
(set (match_operand:HI 0 "register_operand" "=r")
(subreg:HI (match_dup 1) 0))
(set (match_operand:HI 3 "register_operand" "=r")
(subreg:HI (match_dup 1) 2))]
"TARGET_40_PLUS"
"")
and I'm pretty sure this worked at some point in the past.
paul
next prev parent reply other threads:[~2023-01-09 14:23 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-09 12:20 Stefan Kanthak
2023-01-09 13:10 ` LIU Hao
2023-01-09 13:19 ` Stefan Kanthak
2023-01-09 14:23 ` Paul Koning [this message]
2023-01-09 15:20 ` Stefan Kanthak
2023-01-09 15:30 ` Paul Koning
2023-01-09 16:27 ` Stefan Kanthak
2023-01-10 16:49 ` Paul Koning
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