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From: Peter Maydell <peter.maydell@linaro.org>
To: Raghavendra D Prabhu <raghu.prabhu13@gmail.com>
Cc: qemu-devel@nongnu.org, Raghavendra D Prabhu <rprabhu@wnohang.net>,
	kvm@vger.kernel.org
Subject: Re: [Qemu-devel] [PATCH 2/3] Add fno-strict-overflow
Date: Mon, 4 Jul 2011 23:38:30 +0100	[thread overview]
Message-ID: <CAFEAcA_mDcMgBzyaXwO_qAdmAA4GagQoah7TFbSdGZbMiEa8cw@mail.gmail.com> (raw)
In-Reply-To: <bfecbc89c76320fe48a0efaa21fef7085b0d04bb.1309816302.git.rprabhu@wnohang.net>

On 4 July 2011 23:00, Raghavendra D Prabhu <raghu.prabhu13@gmail.com> wrote:
> This is to avoid gcc optimizating out the comparison in assert,
> due to assumption of signed overflow being undefined by default (-Werror=strict-overflow).

>--- a/Makefile.hw
>+++ b/Makefile.hw
>@@ -9,7 +9,7 @@ include $(SRC_PATH)/rules.mak
>
> $(call set-vpath, $(SRC_PATH):$(SRC_PATH)/hw)
>
> -QEMU_CFLAGS+=-I.. -I$(SRC_PATH)/fpu
> +QEMU_CFLAGS+=-I.. -I$(SRC_PATH)/fpu -fno-strict-overflow

Can you give a more detailed description of the problem this is trying
to solve? I think it would be nicer if we could remove the assumptions
about signed overflows instead, if that's practical.

(Also, if we do want to add this compiler flag then it ought to be
done in configure I think, as we do for -fno-strict-aliasing.)

-- PMM

WARNING: multiple messages have this Message-ID (diff)
From: Peter Maydell <peter.maydell@linaro.org>
To: Raghavendra D Prabhu <raghu.prabhu13@gmail.com>
Cc: Raghavendra D Prabhu <rprabhu@wnohang.net>,
	qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: [Qemu-devel] [PATCH 2/3] Add fno-strict-overflow
Date: Mon, 4 Jul 2011 23:38:30 +0100	[thread overview]
Message-ID: <CAFEAcA_mDcMgBzyaXwO_qAdmAA4GagQoah7TFbSdGZbMiEa8cw@mail.gmail.com> (raw)
In-Reply-To: <bfecbc89c76320fe48a0efaa21fef7085b0d04bb.1309816302.git.rprabhu@wnohang.net>

On 4 July 2011 23:00, Raghavendra D Prabhu <raghu.prabhu13@gmail.com> wrote:
> This is to avoid gcc optimizating out the comparison in assert,
> due to assumption of signed overflow being undefined by default (-Werror=strict-overflow).

>--- a/Makefile.hw
>+++ b/Makefile.hw
>@@ -9,7 +9,7 @@ include $(SRC_PATH)/rules.mak
>
> $(call set-vpath, $(SRC_PATH):$(SRC_PATH)/hw)
>
> -QEMU_CFLAGS+=-I.. -I$(SRC_PATH)/fpu
> +QEMU_CFLAGS+=-I.. -I$(SRC_PATH)/fpu -fno-strict-overflow

Can you give a more detailed description of the problem this is trying
to solve? I think it would be nicer if we could remove the assumptions
about signed overflows instead, if that's practical.

(Also, if we do want to add this compiler flag then it ought to be
done in configure I think, as we do for -fno-strict-aliasing.)

-- PMM

  reply	other threads:[~2011-07-04 22:38 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-04 21:59 [PATCH 0/3] Build fixes Raghavendra D Prabhu
2011-07-04 21:59 ` [Qemu-devel] " Raghavendra D Prabhu
2011-07-04 22:00 ` [PATCH 1/3] Avoid the use of deprecated gnutls gnutls_*_set_priority functions Raghavendra D Prabhu
2011-07-04 22:00   ` [Qemu-devel] " Raghavendra D Prabhu
2011-08-22  8:26   ` Stefan Hajnoczi
2011-08-22  8:26     ` [Qemu-devel] " Stefan Hajnoczi
2011-08-22 10:13     ` Gerd Hoffmann
2011-08-22 10:13       ` [Qemu-devel] " Gerd Hoffmann
2011-08-25 10:54   ` Stefan Hajnoczi
2011-08-25 10:54     ` [Qemu-devel] " Stefan Hajnoczi
2011-08-25 11:02     ` Daniel P. Berrange
2011-08-25 11:02       ` [Qemu-devel] " Daniel P. Berrange
2011-07-04 22:00 ` [PATCH 2/3] Add fno-strict-overflow Raghavendra D Prabhu
2011-07-04 22:00   ` [Qemu-devel] " Raghavendra D Prabhu
2011-07-04 22:38   ` Peter Maydell [this message]
2011-07-04 22:38     ` Peter Maydell
2011-07-05  5:41     ` Stefan Hajnoczi
2011-07-05  5:41       ` Stefan Hajnoczi
2011-07-05  9:34       ` Stefan Hajnoczi
2011-07-05  9:34         ` Stefan Hajnoczi
2011-07-05 15:36     ` Raghavendra D Prabhu
2011-07-05 20:30       ` Stefan Hajnoczi
2011-07-07 21:51         ` Raghavendra D Prabhu
2011-07-04 22:00 ` [PATCH 3/3] Avoid Wunsed-but-set warnings (or errors in case of Werror) Raghavendra D Prabhu
2011-07-04 22:00   ` [Qemu-devel] " Raghavendra D Prabhu
2011-07-05  6:15   ` Markus Armbruster
2011-07-05  6:15     ` Markus Armbruster
2011-07-05  7:02     ` Peter Maydell
2011-07-05  7:02       ` Peter Maydell
2011-07-05  7:49       ` Markus Armbruster
2011-07-05  8:05         ` Paolo Bonzini

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