Re: [Buildroot] [PATCH 2/2] package/glibc: riscv w/ ISA RVV needs gcc >= 15

From: Thomas Petazzoni via buildroot <buildroot@buildroot.org>
To: Romain Naour <romain.naour@smile.fr>
Cc: arnout@rnout.be, Julien Olivain <ju.o@free.fr>, buildroot@buildroot.org
Subject: Re: [Buildroot] [PATCH 2/2] package/glibc: riscv w/ ISA RVV needs gcc >= 15
Date: Tue, 13 Oct 2026 10:31:33 +0200	[thread overview]
Message-ID: <as3sD0VIZZwk-tXn@windsurf> (raw)
In-Reply-To: <20260607213030.1509913-2-romain.naour@smile.fr>

Hello,

Adding some maintainers in Cc.

On Sun, Jun 07, 2026 at 11:30:30PM +0200, Romain Naour via buildroot wrote:
> The sipeed_licheepi_4a defconfig doesn't build since the glibc version
> bump to 2.43 [1]. Glibc increased the minimal gcc version for riscv
> w/ ISA RVV in commit [2].
> 
> Add a new glibc dependency on gcc 15 when ISA RVV is enabled.
> 
> [1] 227378b5930b681c79a13476ae60a98753a98a03
> [2] https://sourceware.org/git/?p=glibc.git;a=commit;h=47975914fb106b83c42bc0baf6435a0944a23d30
> 
> Signed-off-by: Romain Naour <romain.naour@smile.fr>
> ---
>  package/glibc/Config.in | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/package/glibc/Config.in b/package/glibc/Config.in
> index 2bf44bb70b..8e5b08ab7f 100644
> --- a/package/glibc/Config.in
> +++ b/package/glibc/Config.in
> @@ -27,6 +27,9 @@ config BR2_PACKAGE_GLIBC_ARCH_SUPPORTS
>  	# glibc needs atomic instructions, and does not support
>  	# single-precision floating point ABIs (ilp32f and lp64f)
>  	depends on (BR2_RISCV_ISA_RVA && !BR2_RISCV_ABI_ILP32F && !BR2_RISCV_ABI_LP64F) || !BR2_riscv
> +	# glibc >= 2.43 needs at gcc >= 15 when Vector
> +	# Instructions (V) are enabled.
> +	depends on (BR2_RISCV_ISA_RVV && BR2_TOOLCHAIN_GCC_AT_LEAST_15) || !BR2_riscv

This will hide glibc if gcc 15.x is not used. I was wondering if it
would make more sense to turn things around and hide gcc 14.x instead
if glibc is used on RISC-V RVV-enabled platforms?

Peter, Arnout, Julien, thoughts?

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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