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authorJoseph Myers <joseph@codesourcery.com>2019-08-21 12:06:44 +0000
committerJoseph Myers <joseph@codesourcery.com>2019-08-21 12:06:44 +0000
commitf9fabc1b02d252d5d9b2e0df406bb394b8a7b46a (patch)
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Add tgmath.h macros for narrowing functions.
When adding some of the TS 18661 narrowing functions for glibc 2.28, I deferred adding corresponding <tgmath.h> support because of unresolved questions about the specification for those type-generic macros, especially in relation to _FloatN and _FloatNx types. Those issues are now clarified in the response to Clarification Request 13 to TS 18661-3, and this patch adds the deferred tgmath.h support. As with other tgmath.h macros, there are fairly straightforward implementations based on __builtin_tgmath for GCC 8 and later, which result in exactly the right function being called in each case, and more complicated implementations for GCC 7 and earlier, which generally result in a function being called whose arguments have the right format (i.e. an alias for the right function), but which might not be exactly the function name specified by TS 18661. In one case with older compilers (f32x* macros, where the type _Float64x exists and all the arguments have type _Float32 or _Float32x), there is a further relaxation and the function called may have arguments narrower than the one specified by the TS, but still wide enough to represent the arguments exactly, so the result of the call is unchanged (as this does not affect any case where rounding of integer arguments might be involved). With GCC 6 or before this is inherently unavoidable (but still harmless and not detectable by how the compiled program behaves, unless it redefines the functions in question like the testcases do) because _Float32x and _Float64 are both typedefs for double in that case but the specified semantics result in different functions, with different argument formats, being called for those two argument types. Tests for the new macros are handled through gen-tgmath-tests.py, which deals with the special-case handling for older GCC. Tested as follows: with the full glibc testsuite on x86_64 and x86 (with GCC 6, 7 and 8); with the math/ tests on aarch64 and arm (with GCC 6, 7 and 8); with build-many-glibcs.py (with GCC 6, 7 and 9). * math/tgmath.h [__HAVE_FLOAT128X]: Give error. [(__HAVE_FLOAT64X && !__HAVE_FLOAT128) || (__HAVE_FLOAT128 && !__HAVE_FLOAT64X)]: Likewise. (__TGMATH_2_NARROW_F): Likewise. (__TGMATH_2_NARROW_D): New macro. (__TGMATH_2_NARROW_F16): Likewise. (__TGMATH_2_NARROW_F32): Likewise. (__TGMATH_2_NARROW_F64): Likewise. (__TGMATH_2_NARROW_F32X): Likewise. (__TGMATH_2_NARROW_F64X): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_NARROW_FUNCS_F): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_NARROW_FUNCS_F16): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_NARROW_FUNCS_F32): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_NARROW_FUNCS_F64): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_NARROW_FUNCS_F32X): Likewise. [__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (fadd): Likewise. [__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (dadd): Likewise. [__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (fdiv): Likewise. [__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (ddiv): Likewise. [__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (fmul): Likewise. [__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (dmul): Likewise. [__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (fsub): Likewise. [__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (dsub): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT16] (f16add): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT16] (f16div): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT16] (f16mul): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT16] (f16sub): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32] (f32add): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32] (f32div): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32] (f32mul): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32] (f32sub): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64 && (__HAVE_FLOAT64X || __HAVE_FLOAT128)] (f64add): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64 && (__HAVE_FLOAT64X || __HAVE_FLOAT128)] (f64div): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64 && (__HAVE_FLOAT64X || __HAVE_FLOAT128)] (f64mul): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64 && (__HAVE_FLOAT64X || __HAVE_FLOAT128)] (f64sub): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32X] (f32xadd): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32X] (f32xdiv): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32X] (f32xmul): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32X] (f32xsub): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64X && (__HAVE_FLOAT128X || __HAVE_FLOAT128)] (f64xadd): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64X && (__HAVE_FLOAT128X || __HAVE_FLOAT128)] (f64xdiv): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64X && (__HAVE_FLOAT128X || __HAVE_FLOAT128)] (f64xmul): Likewise. [__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64X && (__HAVE_FLOAT128X || __HAVE_FLOAT128)] (f64xsub): Likewise. * math/gen-tgmath-tests.py (Type): Add members non_standard_real_argument_types_list, long_double_type, complex_float64_type and float32x_ext_type. (Type.__init__): Set the new members. (Type.floating_type): Add new argument floatn. (Type.real_floating_type): Likewise. (Type.can_combine_types): Likewise. (Type.combine_types): Likewise. (Type.init_types): Create internal Float32x_ext type. (Tests.__init__): Define Float32x_ext in generated C code. (Tests.add_tests): Handle narrowing functions. (Tests.add_all_tests): Likewise. (Tests.tests_text): Allow variation in mant_dig for narrowing functions with compilers before GCC 8. * math/Makefile (tgmath3-narrow-types): New variable. (tgmath3-narrow-macros): Likewise. (tgmath3-macros): Add $(tgmath3-narrow-macros).
Diffstat (limited to 'NEWS')
-rw-r--r--NEWS5
1 files changed, 5 insertions, 0 deletions
diff --git a/NEWS b/NEWS
index 045720b3fb..a64b89986a 100644
--- a/NEWS
+++ b/NEWS
@@ -16,6 +16,11 @@ Major new features:
liable to change. Features from C2X are also enabled by _GNU_SOURCE, or
by compiling with "gcc -std=gnu2x".
+* The <math.h> functions that round their results to a narrower type now
+ have corresponding type-generic macros in <tgmath.h>, as defined in TS
+ 18661-1:2014 and TS 18661-3:2015 as amended by the resolution of
+ Clarification Request 13 to TS 18661-3.
+
Deprecated and removed features, and other changes affecting compatibility:
* The totalorder and totalordermag functions, and the corresponding