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Message-ID: <559274C3.4080305@codesourcery.com>
Date: Tue, 30 Jun 2015 11:03:00 -0000
From: Chung-Lin Tang <cltang@codesourcery.com>
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To: Eric Botcazou <ebotcazou@adacore.com>
CC: <gcc-patches@gcc.gnu.org>, Sandra Loosemore <sandra@codesourcery.com>,	Kito Cheng <kito.cheng@gmail.com>, Jeff Law <law@redhat.com>, Marcus Shawcroft <Marcus.Shawcroft@arm.com>, Richard Earnshaw	<Richard.Earnshaw@arm.com>, "Schmidt, Bernd - Code Sourcery"	<bernds@codesourcery.com>
Subject: Re: [patch] fix regrename pass to ensure renamings produce valid insns
References: <5581AA41.7010201@codesourcery.com> <55922571.2050808@codesourcery.com> <5592287F.4050203@codesourcery.com> <2385820.32MGCG8euH@polaris>
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On 2015/6/30 05:06 PM, Eric Botcazou wrote:
>> I notice the way gcc_assert() is defined in system.h now, the test won't
>> disappear even when runtime checks are disabled, though you might still
>> adjust it to avoid any programmer confusion.
> 
> It will disappear at run time, see the definition:
> 
> /* Include EXPR, so that unused variable warnings do not occur.  */
> #define gcc_assert(EXPR) ((void)(0 && (EXPR)))
> 
> so you really need to use a separate variable.
> 

I was referring to this one:
#if ENABLE_ASSERT_CHECKING
...	
#elif (GCC_VERSION >= 4005)
#define gcc_assert(EXPR)                                                \
  ((void)(__builtin_expect (!(EXPR), 0) ? __builtin_unreachable (), 0 : 0))
#else
...

But yeah, I guess older GCCs could be used to build a toolchain,
so a separate variable should be used.

Chung-Lin