Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753489Ab3JJF4A (ORCPT ); Thu, 10 Oct 2013 01:56:00 -0400 Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:54155 "EHLO LGEMRELSE7Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751215Ab3JJFz7 (ORCPT ); Thu, 10 Oct 2013 01:55:59 -0400 X-AuditID: 9c930197-b7b88ae0000032c4-f3-5256416d0d76 From: Namhyung Kim To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Arnaldo Carvalho de Melo , David Ahern , Jiri Olsa Subject: Re: [PATCH 07/52] tools/perf/build: Split out feature check: 'volatile-register-var' References: <1381227082-22039-1-git-send-email-mingo@kernel.org> <1381227082-22039-8-git-send-email-mingo@kernel.org> Date: Thu, 10 Oct 2013 14:55:57 +0900 In-Reply-To: <1381227082-22039-8-git-send-email-mingo@kernel.org> (Ingo Molnar's message of "Tue, 8 Oct 2013 12:10:37 +0200") Message-ID: <87d2ndk6tu.fsf@sejong.aot.lge.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1442 Lines: 39 On Tue, 8 Oct 2013 12:10:37 +0200, Ingo Molnar wrote: > -ifeq ($(call try-cc,$(SOURCE_HELLO),$(CFLAGS) -Werror -Wvolatile-register-var,-Wvolatile-register-var),y) > +ifeq ($(feature-volatile-register-var), 1) > CFLAGS += -Wvolatile-register-var > endif > > diff --git a/tools/perf/config/feature-checks/Makefile b/tools/perf/config/feature-checks/Makefile > index 46b7650..5693299 100644 > --- a/tools/perf/config/feature-checks/Makefile > +++ b/tools/perf/config/feature-checks/Makefile > @@ -3,6 +3,7 @@ FILES= \ > test-hello \ > test-stackprotector-all \ > test-stackprotector \ > + test-volatile-register-var \ > test-libnuma > > CC := $(CC) -MD > @@ -22,6 +23,9 @@ test-stackprotector-all: > test-stackprotector: > $(BUILD) -Werror -fstack-protector > > +test-volatile-register-var: > + $(BUILD) -Werror -Wvolatile-register-var I'm not sure this test is necessary at all. The gcc manpage says this warning is enabled by -Wall, and we add -Wall to CFLAGS before doing feature checks. So all gcc versions that support -Wvolatile-register-var enables it by default without this check and older gcc versions will always fail the feature check. Thanks, Namhyung -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/