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| author | Marius Hillenbrand <mhillen@linux.ibm.com> | 2020-12-01 15:36:34 +0100 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2020-12-03 19:07:24 -0500 |
| commit | 738c4e945c1218559d36b83cbaba11459fad89c9 (patch) | |
| tree | 58c66e2603b4c9c0ebde61ea79f6cf8dece07261 /arch | |
| parent | 821083ac7b54eaa040d5a8ddc67c6206a175e0ca (diff) | |
| download | musl-738c4e945c1218559d36b83cbaba11459fad89c9.zip musl-738c4e945c1218559d36b83cbaba11459fad89c9.tar.gz musl-738c4e945c1218559d36b83cbaba11459fad89c9.tar.bz2 | |
s390x: derive float_t from compiler or default to float
float_t should represent the type that is used to evaluate float
expressions internally. On s390x, float_t is currently set to double.
In contrast, the isa supports single-precision float operations and
compilers by default evaluate float in single precision, which
violates the C standard (sections 5.2.4.2.2 and 7.12 in C11/C17, to be
precise). With -fexcess-precision=standard, gcc evaluates float in
double precision, which aligns with the standard yet at the cost of
added conversion instructions.
gcc-11 will drop the special case to retrofit double precision
behavior for -fexcess-precision=standard so that __FLT_EVAL_METHOD__
will be 0 on s390x in any scenario.
To improve standards compliance and compatibility with future compiler
direction, this patch changes the definition of float_t to be derived
from the compiler's __FLT_EVAL_METHOD__.
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390x/bits/alltypes.h.in | 4 | ||||
| -rw-r--r-- | arch/s390x/bits/float.h | 6 |
2 files changed, 9 insertions, 1 deletions
diff --git a/arch/s390x/bits/alltypes.h.in b/arch/s390x/bits/alltypes.h.in index 15d18c8..6c0eb7f 100644 --- a/arch/s390x/bits/alltypes.h.in +++ b/arch/s390x/bits/alltypes.h.in @@ -9,7 +9,11 @@ TYPEDEF int wchar_t; #endif +#if defined(__FLT_EVAL_METHOD__) && __FLT_EVAL_METHOD__ == 1 TYPEDEF double float_t; +#else +TYPEDEF float float_t; +#endif TYPEDEF double double_t; TYPEDEF struct { long long __ll; long double __ld; } max_align_t; diff --git a/arch/s390x/bits/float.h b/arch/s390x/bits/float.h index 90b73be..e188cb6 100644 --- a/arch/s390x/bits/float.h +++ b/arch/s390x/bits/float.h @@ -1,4 +1,8 @@ -#define FLT_EVAL_METHOD 1 +#ifdef __FLT_EVAL_METHOD__ +#define FLT_EVAL_METHOD __FLT_EVAL_METHOD__ +#else +#define FLT_EVAL_METHOD 0 +#endif #define LDBL_TRUE_MIN 6.47517511943802511092443895822764655e-4966L #define LDBL_MIN 3.36210314311209350626267781732175260e-4932L |