Use long double not double for _Float64 with old GCC if values the same

System Internals / glibc - Joseph Myers [codesourcery.com] - 5 December 2017 21:52 EST

If double, long double and _Float64 all have the same set of values, TS 18661-3 requires the usual arithmetic conversions on long double and _Float64 to produce _Float64. For this to be the case when building with a compiler without a distinct _Float64 type, _Float64 must be a typedef for long double, not for double. (_Float32x, however, must be double in such a case, not long double, because the usual arithmetic conversions on _Float32x and double must produce double.)

This patch adjusts the fallback definition of _Float64 and associated macros accordingly in that case, to fix the build of test-tgmath3 with GCC 6 for such a configuration. Tested in conjunction with _Float64 changes with build-many-glibcs.py for arm-linux-gnueabi, to make sure the issue with test-tgmath3 is fixed. Also tested for x86_64.

- bits/floatn-common.h: Include . [__HAVE_FLOAT64 && (!__GNUC_PREREQ (7, 0) || defined __cplusplus) && __NO_LONG_DOUBLE_MATH] (__f64): Use suffix 'l'. [__HAVE_FLOAT64 && (!__GNUC_PREREQ (7, 0) || defined __cplusplus) && __NO_LONG_DOUBLE_MATH] (__CFLOAT64): Use _Complex long double. [__HAVE_FLOAT64 && (!__GNUC_PREREQ (7, 0) || defined __cplusplus) && __NO_LONG_DOUBLE_MATH] (_Float64): Use long double. [__HAVE_FLOAT64 && !__GNUC_PREREQ (7, 0) && __NO_LONG_DOUBLE_MATH] (__builtin_huge_valf64): Use __builtin_huge_vall. [__HAVE_FLOAT64 && !__GNUC_PREREQ (7, 0) && __NO_LONG_DOUBLE_MATH] (__builtin_inff64): Use __builtin_infl. [__HAVE_FLOAT64 && !__GNUC_PREREQ (7, 0) && __NO_LONG_DOUBLE_MATH] (__builtin_nanf64): Use __builtin_nanl. [__HAVE_FLOAT64 && !__GNUC_PREREQ (7, 0) && __NO_LONG_DOUBLE_MATH] (__builtin_nansf64): Use __builtin_nansl.

f778723496 Use long double not double for _Float64 with old GCC if values the same.
ChangeLog | 18 ++++++++++++++++++
bits/floatn-common.h | 51 ++++++++++++++++++++++++++++++++++++++++++---------
2 files changed, 60 insertions(+), 9 deletions(-)

Upstream: sourceware.org


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