[PATCH] Builtin function roundeven folding implementation

[Tejas Joshi]

Hi.
This patch includes implementation of new function roundeven along
with two utility functions. The patch bootstraps on x86_64-linux-gnu
and passes regression tests.

Thanks,
Tejas

gcc/ChangeLog:

2019-06-12  Tejas Joshi  <tejasjoshi9673@gmail.com>

    * builtins.c (mathfn_built_in_2): Added CASE_MATHFN for ROUNDEVEN.
    * builtins.def: Added function definitions for roundeven function
    variants.
    * fold-const-call.c (fold_const_call_ss): Added case for function
    call and fold_const_conversion call for roundeven function.
    * fold-const.c (negate_mathfn_p): Added case for roundeven function.
    (tree_call_nonnegative_warnv_p): Added case for roundeven function.
    (integer_valued_real_call_p): Added case for roundeven function.
    * real.c (is_even): New function. Returns true if real number is
    even, otherwise returns false.
    (is_halfway_below): New function. Returns true if real number is
    halfway between two integers, else return false.
    (real_roundeven): New function. Round real number to nearest
    integer, rounding halfway cases towards even.
    * real.h (real_value): Added descriptive comments.
    Added function declaration for roundeven function.

gcc/testsuite/ChangeLog:

2019-06-12  Tejas Joshi  <tejasjoshi9673@gmail.com>

    * gcc.dg/torture/builtin-round-roundeven.c: New test.
    * gcc.dg/torture/builtin-round-roundevenf128.c: New test.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: roundeven.diff
Type: text/x-patch
Size: 9089 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/gcc-patches/attachments/20190628/1a3d7c48/attachment.bin>