From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=IpCr=BM=ispras.ru=amonakov@sourceware.org>
Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84])
	by sourceware.org (Postfix) with ESMTPS id 771103858D35
	for <gcc-patches@gcc.gnu.org>; Tue, 23 May 2023 11:21:47 +0000 (GMT)
DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 771103858D35
Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=ispras.ru
Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=ispras.ru
Received: from [10.10.3.121] (unknown [10.10.3.121])
	by mail.ispras.ru (Postfix) with ESMTPS id 914044076B40;
	Tue, 23 May 2023 11:21:45 +0000 (UTC)
DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru 914044076B40
Date: Tue, 23 May 2023 14:21:45 +0300 (MSK)
From: Alexander Monakov <amonakov@ispras.ru>
To: Richard Biener <richard.guenther@gmail.com>
cc: Marek Polacek <polacek@redhat.com>, Jason Merrill <jason@redhat.com>, 
    gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] c-family: implement -ffp-contract=on
In-Reply-To: <CAFiYyc3S32-Fd5GX7oFQTWZG+HpRe5xUV+9zgeygJoJqKd7qjw@mail.gmail.com>
Message-ID: <0e059864-65ef-2961-04b0-6b0b0ec809e6@ispras.ru>
References: <20230518210331.11564-1-amonakov@ispras.ru> <CAFiYyc1tfKAXmuDq+TRkJs74Ekw=RAPG5WFoT_m3-wGJFq5R3g@mail.gmail.com> <d6a8701a-20f3-cc89-dc92-1b12fb9fdbf7@ispras.ru> <CAFiYyc3S32-Fd5GX7oFQTWZG+HpRe5xUV+9zgeygJoJqKd7qjw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
X-Spam-Status: No, score=-9.2 required=5.0 tests=BAYES_00,GIT_PATCH_0,KAM_DMARC_STATUS,SPF_HELO_NONE,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org
List-Id: <gcc-patches.gcc.gnu.org>


On Tue, 23 May 2023, Richard Biener wrote:
> > Ah, no, I deliberately decided against that, because that way we would go
> > via gimplify_arg, which would emit all side effects in *pre_p. That seems
> > wrong if arguments had side-effects that should go in *post_p.
> 
> Ah, true - that warrants a comment though.

Incrementally fixed up in my tree like this:

diff --git a/gcc/c-family/c-gimplify.cc b/gcc/c-family/c-gimplify.cc
index f7635d3b0c..17b0610a89 100644
--- a/gcc/c-family/c-gimplify.cc
+++ b/gcc/c-family/c-gimplify.cc
@@ -803,6 +803,7 @@ c_gimplify_expr (tree *expr_p, gimple_seq *pre_p ATTRIBUTE_UNUSED,
                else
                  ops[2] = build1 (NEGATE_EXPR, type, ops[2]);
              }
+           /* Avoid gimplify_arg: it emits all side effects into *PRE_P.  */
            for (auto &&op : ops)
              if (gimplify_expr (&op, pre_p, post_p, is_gimple_val, fb_rvalue)
                  == GS_ERROR)

Alexander