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Re: [PATCH v2 00/18] Use GCC builtins for some math functions if desired.


On 12/10/19 8:18 PM, Adhemerval Zanella wrote:


On 09/12/2019 09:45, Stefan Liebler wrote:
Hi,

this patch-series moves the nearbyint, rint, floor, ceil, trunc and round implementation from sysdeps/ieee754/dbl-64/wordsize-64 to sysdeps/ieee754/dbl-64/ as proposed by Adhemerval:
ttps://www.sourceware.org/ml/libc-alpha/2019-11/msg00085.html

It also introduces the math-use-builtins.h header with __USE_<SYMBOL>_BUILTIN macros which allows to just use GCC __builtin_<SYMBOL> instead of the current common-code implementation.  There is a float, double, long double and _Float128 version of this macro for each <SYMBOL>.

The generic math-use-builtins.h header is defining all those macros to 0 in order to use the current common-code implenetation.  If an architecture wants to use the builtins, an architecture specific math-use-builtins.h needs to be created (e.g. done for s390) where those macros are defined to 1.

Changes compared to first version (see https://www.sourceware.org/ml/libc-alpha/2019-12/msg00029.html) due to review from:
Joseph Myers:
* The copysign builtins are now used unconditionally for float, double and long double.  For _Float128 the macro is defined to 1 if build with GCC >= 7.

Adhemerval Zanella:
* Some static array definitions like TWO52 in s_nearbyint.c are moved inside the !USE_NEARBYINT_BUILTIN within the function.
* The s390 math-use-builtins.h header is now replicating the USE_XYZ* macros for !HAVE_S390_MIN_Z196_ZARCH_ASM_SUPPORT instead of just including the generic header file.
* The changes regarding code style in the "Use GCC builtins for xyz functions if desired" patches are splitted out into the new patches "Adjust s_XYZ.c regarding code style."

Hi Stefan,

I reviewed the whole series and it looks good.  I haven't reviewed again the
parts 01 to 07 since they are essentially the same as previous version and
they are already reviewed.


Hi Adhemerval,

Thanks for the review. Yes, the first parts have not changed compared to the first version.

I've just committed the patches.

Bye
Stefan


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