[Buildroot] [PATCH RESEND] toolchain: use -ffp-contract=off on MIPS in the wrapper when needed

From: Baruch Siach <baruch@tkos.co.il>
To: buildroot@busybox.net
Subject: [Buildroot] [PATCH RESEND] toolchain: use -ffp-contract=off on MIPS in the wrapper when needed
Date: Thu, 8 Mar 2018 14:33:36 +0200	[thread overview]
Message-ID: <20180308123336.ywdsi5b5lo4iwjvv@tarshish> (raw)
In-Reply-To: <20180308121430.20013-1-ezequiel@vanguardiasur.com.ar>

Hi Ezequiel,

On Thu, Mar 08, 2018 at 09:14:30AM -0300, Ezequiel Garcia wrote:
> From: Johannes Schmitz <johannes.schmitz1@gmail.com>
> 
> This fix is necessary for to build for MIPS, for example for the MIPS
> XBurst architecture used on ci20 boards.
> 
> GCC has replaced (no)mfused-madd with ffp-contract.
> Find more details and a long discussion at
> https://gcc.gnu.org/ml/gcc-patches/2015-06/msg00876.html
> 
> Signed-off-by: Johannes Schmitz <johannes.schmitz1@gmail.com>
> Tested-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
> ---
> Ci20 builds are currently broken without this patch.
> 
>  toolchain/toolchain-wrapper.c  | 3 ---
>  toolchain/toolchain-wrapper.mk | 4 ++++
>  2 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/toolchain/toolchain-wrapper.c b/toolchain/toolchain-wrapper.c
> index 2928ea42d0e6..04b263199547 100644
> --- a/toolchain/toolchain-wrapper.c
> +++ b/toolchain/toolchain-wrapper.c
> @@ -79,9 +79,6 @@ static char *predef_args[] = {
>  #ifdef BR_OMIT_LOCK_PREFIX
>  	"-Wa,-momit-lock-prefix=yes",
>  #endif
> -#ifdef BR_NO_FUSED_MADD

Since you remove this macro reference, ...

> -	"-mno-fused-madd",
> -#endif
>  #ifdef BR_BINFMT_FLAT
>  	"-Wl,-elf2flt",
>  #endif
> diff --git a/toolchain/toolchain-wrapper.mk b/toolchain/toolchain-wrapper.mk
> index 7f72a0cadec9..7faa033f605c 100644
> --- a/toolchain/toolchain-wrapper.mk
> +++ b/toolchain/toolchain-wrapper.mk
> @@ -28,8 +28,12 @@ endif
>  
>  # Avoid FPU bug on XBurst CPUs
>  ifeq ($(BR2_mips_xburst),y)
> +ifeq ($(BR2_TOOLCHAIN_GCC_AT_LEAST_4_6),y)
> +TOOLCHAIN_WRAPPER_ARGS += -DBR_FP_CONTRACT_OFF
> +else
>  TOOLCHAIN_WRAPPER_ARGS += -DBR_NO_FUSED_MADD

... why not remove it here as well?

>  endif
> +endif
>  
>  ifeq ($(BR2_CCACHE_USE_BASEDIR),y)
>  TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE_BASEDIR='"$(BASE_DIR)"'

baruch

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