From b0216d3e4d98a3528bad428c22ff96fcbcc102a4 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Wed, 23 Nov 2016 00:28:30 +0000 Subject: Fix default float_t definition (bug 20855). The default (top-level) version of bits/mathdef.h defines float_t to double. It is used on ColdFire, MicroBlaze, Nios II and SH3, all of which define FLT_EVAL_METHOD to 0, so float_t should be float (and C11 requires a certain correspondence between these typedefs and FLT_EVAL_METHOD values). I proposed fixing this default in , with no objections from architecture maintainers, and this patch makes that fix. As noted in the NEWS entry added, this might affect the ABIs of non-glibc libraries (ImageMagick has been mentioned in gcc-patches discussion of the S/390 case - which is unaffected by this patch), but as noted in my previous message, affected libraries would have problems with -mfpmath=sse anyway on 32-bit x86. A (compilation) testcase is added to verify the required correspondence of typedefs to FLT_EVAL_METHOD values. This test is built with -fexcess-precision=standard to avoid any issues with GCC 7 on S/390 providing a more accurate FLT_EVAL_METHOD definition in the default (no excess precision) mode. (This will also be usable to test a fix for the recently reported bug about these typedefs on x86_64 -mfpmath=387, as architecture-specific tests can be added that It is entirely possible that the fixed default makes some architecture-specific versions of bits/mathdef.h semantically equivalent to the default version and so no longer required. I don't intend to investigate that separately from the refactoring I proposed in , which will create as few header variants as possible for each group of definitions. Tested (compilation only) with build-many-glibcs.py. [BZ #20855] * bits/mathdef.h (float_t): Define to float. * math/test-flt-eval-method.c: New file. * math/Makefile (tests): Add test-flt-eval-method. (CFLAGS-test-flt-eval-method.c): New variable. --- NEWS | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'NEWS') diff --git a/NEWS b/NEWS index b99fc69..6e256ae 100644 --- a/NEWS +++ b/NEWS @@ -65,6 +65,11 @@ Version 2.25 - NaN functions: getpayload, getpayloadf, getpayloadl, setpayload, setpayloadf, setpayloadl. +* On ColdFire, MicroBlaze, Nios II and SH3, the float_t type is now defined + to float instead of double. This does not affect the ABI of any libraries + that are part of the GNU C Library, but may affect the ABI of other + libraries that use this type in their interfaces. + * The functions strfromd, strfromf, and strfroml, from ISO/IEC TS 18661-1:2014, are added to libc. They convert a floating-point number into string. -- cgit v1.1