[gcc r13-3569] builtins: Add __builtin_nextafterf16b builtin

[Jakub Jelinek <jakub@gcc.gnu.org>]

https://gcc.gnu.org/g:29490c2a1dc00944f2420eb59374705f180a2e53

commit r13-3569-g29490c2a1dc00944f2420eb59374705f180a2e53
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Oct 31 09:07:04 2022 +0100

    builtins: Add __builtin_nextafterf16b builtin
    
    The following patch adds another needed builtin.
    The earlier patch adds among other things __builtin_nextafterf16
    builtin which we need in order to constexpr evaluate
    std::nextafter(_Float16) overload (patch for that has been posted already).
    While there is inline implementation of the overload, it isn't constant
    evaluation friendly, and the builtin doesn't need libm implementation
    because it will be used only during constant expression evaluation.
    We need the same thing also for std::nextafter(__gnu_cxx::__bfloat16_t)
    though and this patch does that.
    
    2022-10-31  Jakub Jelinek  <jakub@redhat.com>
    
            * builtin-types.def (BT_FN_BFLOAT16_BFLOAT16_BFLOAT16): New.
            * builtins.def (BUILT_IN_NEXTAFTERF16B): New builtin.
            * fold-const-call.cc (fold_const_call_sss): Handle
            CFN_BUILT_IN_NEXTAFTERF16B.

Diff:
---
 gcc/builtin-types.def  | 2 ++
 gcc/builtins.def       | 1 +
 gcc/fold-const-call.cc | 1 +
 3 files changed, 4 insertions(+)

diff --git a/gcc/builtin-types.def b/gcc/builtin-types.def
index 2dbed8ae05c..81460e1ed2b 100644
--- a/gcc/builtin-types.def
+++ b/gcc/builtin-types.def
@@ -461,6 +461,8 @@ DEF_FUNCTION_TYPE_2 (BT_FN_FLOAT64X_FLOAT64X_FLOAT64X,
 		     BT_FLOAT64X, BT_FLOAT64X, BT_FLOAT64X)
 DEF_FUNCTION_TYPE_2 (BT_FN_FLOAT128X_FLOAT128X_FLOAT128X,
 		     BT_FLOAT128X, BT_FLOAT128X, BT_FLOAT128X)
+DEF_FUNCTION_TYPE_2 (BT_FN_BFLOAT16_BFLOAT16_BFLOAT16,
+		     BT_BFLOAT16, BT_BFLOAT16, BT_BFLOAT16)
 DEF_FUNCTION_TYPE_2 (BT_FN_FLOAT_FLOAT_FLOATPTR,
 		     BT_FLOAT, BT_FLOAT, BT_FLOAT_PTR)
 DEF_FUNCTION_TYPE_2 (BT_FN_DOUBLE_DOUBLE_DOUBLEPTR,
diff --git a/gcc/builtins.def b/gcc/builtins.def
index 42c005a7651..49973151bfe 100644
--- a/gcc/builtins.def
+++ b/gcc/builtins.def
@@ -591,6 +591,7 @@ DEF_C99_BUILTIN        (BUILT_IN_NEXTAFTERF, "nextafterf", BT_FN_FLOAT_FLOAT_FLO
 DEF_C99_BUILTIN        (BUILT_IN_NEXTAFTERL, "nextafterl", BT_FN_LONGDOUBLE_LONGDOUBLE_LONGDOUBLE, ATTR_MATHFN_ERRNO)
 #define NEXTAFTER_TYPE(F) BT_FN_##F##_##F##_##F
 DEF_EXT_LIB_FLOATN_NX_BUILTINS (BUILT_IN_NEXTAFTER, "nextafter", NEXTAFTER_TYPE, ATTR_MATHFN_ERRNO)
+DEF_GCC_BUILTIN        (BUILT_IN_NEXTAFTERF16B, "nextafterf16b", BT_FN_BFLOAT16_BFLOAT16_BFLOAT16, ATTR_MATHFN_ERRNO)
 DEF_C99_BUILTIN        (BUILT_IN_NEXTTOWARD, "nexttoward", BT_FN_DOUBLE_DOUBLE_LONGDOUBLE, ATTR_MATHFN_ERRNO)
 DEF_C99_BUILTIN        (BUILT_IN_NEXTTOWARDF, "nexttowardf", BT_FN_FLOAT_FLOAT_LONGDOUBLE, ATTR_MATHFN_ERRNO)
 DEF_C99_BUILTIN        (BUILT_IN_NEXTTOWARDL, "nexttowardl", BT_FN_LONGDOUBLE_LONGDOUBLE_LONGDOUBLE, ATTR_MATHFN_ERRNO)
diff --git a/gcc/fold-const-call.cc b/gcc/fold-const-call.cc
index 5f158152807..ab1b098d6ca 100644
--- a/gcc/fold-const-call.cc
+++ b/gcc/fold-const-call.cc
@@ -1438,6 +1438,7 @@ fold_const_call_sss (real_value *result, combined_fn fn,
 
     CASE_CFN_NEXTAFTER:
     CASE_CFN_NEXTAFTER_FN:
+    case CFN_BUILT_IN_NEXTAFTERF16B:
     CASE_CFN_NEXTTOWARD:
       return fold_const_nextafter (result, arg0, arg1, format);