From: Segher Boessenkool <segher@kernel.crashing.org>
To: Senthil Kumar Selvaraj <senthil.thecoder@gmail.com>
Cc: gcc@gcc.gnu.org, ebotcazou@adacore.com
Subject: Re: Clobber REG_CC only for some constraint alternatives?
Date: Fri, 14 Aug 2020 11:23:07 -0500 [thread overview]
Message-ID: <20200814162307.GM6753@gate.crashing.org> (raw)
In-Reply-To: <87o8nd1npw.fsf@gcc.gnu.org>
Hi!
On Fri, Aug 14, 2020 at 04:46:59PM +0530, Senthil Kumar Selvaraj via Gcc wrote:
> I'm working on porting AVR to MODE_CC,
I'm very happy to see people work on that.
> (define_insn "*mov<mode>_insn_noclobber_flags"
> [(set (match_operand:ALL1 0 "nonimmediate_operand" "=r,d ,q,r")
> (match_operand:ALL1 1 "nox_general_operand" "r,n Ynn,r,q"))
> (clobber (const_int 0))]
This is not correct, clobbers like that are not defined RTL, and are
actually used internally (by combine at least), so this will confuse
that.
If you want to say some alternative does not clobber anything, just use
the constraint "X" for that alternative.
$ grep -r "clobber.*scratch.*X" gcc/config/
HtH,
Segher
next prev parent reply other threads:[~2020-08-14 16:23 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-14 11:16 Senthil Kumar Selvaraj
2020-08-14 15:32 ` Matt Wette
2020-08-14 17:42 ` Pip Cet
2020-08-14 16:23 ` Segher Boessenkool [this message]
2020-08-14 17:47 ` Pip Cet
2020-08-15 0:29 ` Segher Boessenkool
2020-08-15 10:18 ` Pip Cet
2020-08-16 0:50 ` Segher Boessenkool
2020-08-16 18:28 ` Pip Cet
2020-08-17 7:31 ` Senthil Kumar Selvaraj
2020-08-17 9:18 ` Pip Cet
2020-08-18 6:52 ` Senthil Kumar Selvaraj
2020-08-20 11:51 ` Pip Cet
2020-08-20 16:06 ` Senthil Kumar Selvaraj
2020-08-24 18:18 ` Jeff Law
2020-08-26 3:58 ` Hans-Peter Nilsson
2020-08-26 16:20 ` Jeff Law
2020-08-26 18:26 ` Hans-Peter Nilsson
2020-08-26 11:18 ` Pip Cet
2020-08-26 16:21 ` Jeff Law
[not found] ` <87h7so2w0c.fsf@gcc.gnu.org>
2020-08-27 14:48 ` Jeff Law
2020-09-01 19:38 ` Hans-Peter Nilsson
2020-08-17 17:21 ` Segher Boessenkool
2020-08-18 15:17 ` Hans-Peter Nilsson
2020-08-16 3:25 ` Hans-Peter Nilsson
2020-08-19 5:57 ` Senthil Kumar Selvaraj
2020-08-19 22:31 ` Hans-Peter Nilsson
2020-08-20 5:40 ` Senthil Kumar Selvaraj
2020-08-20 8:51 ` Andrew Stubbs
2020-08-20 10:59 ` H.J. Lu
2020-08-20 16:53 ` Hans-Peter Nilsson
2020-08-17 16:45 ` Jeff Law
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