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authorJoseph Myers <joseph@codesourcery.com>2016-11-23 00:28:30 +0000
committerJoseph Myers <joseph@codesourcery.com>2016-11-23 00:28:30 +0000
commitb0216d3e4d98a3528bad428c22ff96fcbcc102a4 (patch)
tree226efd1328173ea09755cc75af10d41ba84909b5 /math/Makefile
parent510abe7b945ddab6f4497e7c097cff677286bb4d (diff)
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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 <https://sourceware.org/ml/libc-alpha/2015-01/msg00499.html>, 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 <https://sourceware.org/ml/libc-alpha/2016-11/msg00745.html>, 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.
Diffstat (limited to 'math/Makefile')
-rw-r--r--math/Makefile3
1 files changed, 2 insertions, 1 deletions
diff --git a/math/Makefile b/math/Makefile
index a5b11e9..fe910ef 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.