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. --- math/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'math/Makefile') diff --git a/math/Makefile b/math/Makefile index a5b11e9177..fe910ef6c0 100644 --- a/math/Makefile +++ b/math/Makefile @@ -158,7 +158,7 @@ tests = test-matherr test-fenv atest-exp atest-sincos atest-exp2 basic-test \ test-fexcept test-fexcept-traps test-fesetexcept \ test-fesetexcept-traps test-fetestexceptflag test-femode \ test-femode-traps test-iszero-excess-precision \ - test-iseqsig-excess-precision $(tests-static) + test-iseqsig-excess-precision test-flt-eval-method $(tests-static) tests-static = test-fpucw-static test-fpucw-ieee-static \ test-signgam-uchar-static test-signgam-uchar-init-static \ test-signgam-uint-static test-signgam-uint-init-static \ @@ -271,6 +271,7 @@ CFLAGS-test-math-iszero.cc = -std=gnu++11 CFLAGS-test-iszero-excess-precision.c = -fexcess-precision=standard CFLAGS-test-iseqsig-excess-precision.c = -fexcess-precision=standard +CFLAGS-test-flt-eval-method.c = -fexcess-precision=standard # The -lieee module sets the _LIB_VERSION_ switch to IEEE mode # for error handling in the -lm functions. -- cgit 1.4.1