From: Jérôme Pouiller Date: Wed, 9 Nov 2016 09:25:08 +0000 (+0100) Subject: python3: fix double format detection X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=7be691623a27087cc89c169e21466a0e66a75eb4;p=buildroot.git python3: fix double format detection Python is not able to detect if compiler double representation is compliant with IEE754: checking whether C doubles are little-endian IEEE 754 binary64... no checking whether C doubles are big-endian IEEE 754 binary64... no checking whether C doubles are ARM mixed-endian IEEE 754 binary64... no Accordingly 'legacy' mode isused. It is possible to check this at runtime by check if 'sys.float_repr_style' contains 'short' or 'legacy'. Calculus correctness is not garanteed with 'legacy'. Problem is better described here: http://stackoverflow.com/questions/29920294/what-causes-pythons-float-repr-style-to-use-legacy https://bugs.python.org/issue7117 However, all gcc architecture use a representation compliant with IEE754. So, we can enable it unconditionnaly. Signed-off-by: Jérôme Pouiller [Thomas: rework condition to not use strip, as suggested by Baruch.] Signed-off-by: Thomas Petazzoni --- diff --git a/package/python3/python3.mk b/package/python3/python3.mk index b3f31c0aa0..f355ae9e6c 100644 --- a/package/python3/python3.mk +++ b/package/python3/python3.mk @@ -126,6 +126,13 @@ PYTHON3_CONF_ENV += \ ac_cv_working_tzset=yes \ ac_cv_prog_HAS_HG=/bin/false +# GCC is always compliant with IEEE754 +ifeq ($(BR2_ENDIAN),"LITTLE") +PYTHON3_CONF_ENV += ac_cv_little_endian_double=yes +else +PYTHON3_CONF_ENV += ac_cv_big_endian_double=yes +endif + # uClibc is known to have a broken wcsftime() implementation, so tell # Python 3 to fall back to strftime() instead. ifeq ($(BR2_TOOLCHAIN_USES_UCLIBC),y)