linux-kernel - Re: [PATCH] lib/mpi: fix build with clang

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Message-ID: <a614598d896b9fcdde4e6a209c7e45a4@agner.ch>
Date:   Sat, 05 Aug 2017 20:31:11 -0700
From:   Stefan Agner <stefan@...er.ch>
To:     herbert@...dor.apana.org.au
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        arnd@...db.de
Subject: Re: [PATCH] lib/mpi: fix build with clang

Hi Herbert,

This still applies fine on 4.13-rc3, any chance to get it merged through
one of your trees?

--
Stefan


On 2017-04-19 20:40, Stefan Agner wrote:
> Use just @ to denote comments which works with gcc and clang.
> Otherwise clang reports an escape sequence error:
>   error: invalid % escape in inline assembly string
> 
> Use %0-%3 as operand references, this avoids:
>   error: invalid operand in inline asm: 'umull ${1:r}, ${0:r}, ${2:r}, ${3:r}'
> 
> Also remove superfluous casts on output operands to avoid warnings
> such as:
>   warning: invalid use of a cast in an inline asm context requiring an l-value
> 
> Signed-off-by: Stefan Agner <stefan@...er.ch>
> ---
> I checked the output of gcc with -S switch before and after this change,
> gcc generated the same assembly.
> 
> --
> Stefan
> 
>  lib/mpi/longlong.h | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/lib/mpi/longlong.h b/lib/mpi/longlong.h
> index 93336502af08..57fd45ab7af1 100644
> --- a/lib/mpi/longlong.h
> +++ b/lib/mpi/longlong.h
> @@ -176,8 +176,8 @@ extern UDItype __udiv_qrnnd(UDItype *, UDItype,
> UDItype, UDItype);
>  #define add_ssaaaa(sh, sl, ah, al, bh, bl) \
>  	__asm__ ("adds %1, %4, %5\n" \
>  		"adc  %0, %2, %3" \
> -	: "=r" ((USItype)(sh)), \
> -		"=&r" ((USItype)(sl)) \
> +	: "=r" (sh), \
> +		"=&r" (sl) \
>  	: "%r" ((USItype)(ah)), \
>  		"rI" ((USItype)(bh)), \
>  		"%r" ((USItype)(al)), \
> @@ -185,15 +185,15 @@ extern UDItype __udiv_qrnnd(UDItype *, UDItype,
> UDItype, UDItype);
>  #define sub_ddmmss(sh, sl, ah, al, bh, bl) \
>  	__asm__ ("subs %1, %4, %5\n" \
>  		"sbc  %0, %2, %3" \
> -	: "=r" ((USItype)(sh)), \
> -		"=&r" ((USItype)(sl)) \
> +	: "=r" (sh), \
> +		"=&r" (sl) \
>  	: "r" ((USItype)(ah)), \
>  		"rI" ((USItype)(bh)), \
>  		"r" ((USItype)(al)), \
>  		"rI" ((USItype)(bl)))
>  #if defined __ARM_ARCH_2__ || defined __ARM_ARCH_3__
>  #define umul_ppmm(xh, xl, a, b) \
> -	__asm__ ("%@ Inlined umul_ppmm\n" \
> +	__asm__ ("@ Inlined umul_ppmm\n" \
>  		"mov	%|r0, %2, lsr #16		@ AAAA\n" \
>  		"mov	%|r2, %3, lsr #16		@ BBBB\n" \
>  		"bic	%|r1, %2, %|r0, lsl #16		@ aaaa\n" \
> @@ -206,19 +206,19 @@ extern UDItype __udiv_qrnnd(UDItype *, UDItype,
> UDItype, UDItype);
>  		"addcs	%|r2, %|r2, #65536\n" \
>  		"adds	%1, %|r1, %|r0, lsl #16\n" \
>  		"adc	%0, %|r2, %|r0, lsr #16" \
> -	: "=&r" ((USItype)(xh)), \
> -		"=r" ((USItype)(xl)) \
> +	: "=&r" (xh), \
> +		"=r" (xl) \
>  	: "r" ((USItype)(a)), \
>  		"r" ((USItype)(b)) \
>  	: "r0", "r1", "r2")
>  #else
>  #define umul_ppmm(xh, xl, a, b) \
> -	__asm__ ("%@ Inlined umul_ppmm\n" \
> -		"umull %r1, %r0, %r2, %r3" \
> -	: "=&r" ((USItype)(xh)), \
> -			"=&r" ((USItype)(xl)) \
> +	__asm__ ("@ Inlined umul_ppmm\n" \
> +		"umull %1, %0, %2, %3" \
> +	: "=&r" (xh), \
> +		"=&r" (xl) \
>  	: "r" ((USItype)(a)), \
> -			"r" ((USItype)(b)) \
> +		"r" ((USItype)(b)) \
>  	: "r0", "r1")
>  #endif
>  #define UMUL_TIME 20