[gcc(refs/users/meissner/heads/work221-float)] Update ChangeLog.float

[Michael Meissner]

https://gcc.gnu.org/g:80ca1d4448807081869404da5a06b682e8a5d051

commit 80ca1d4448807081869404da5a06b682e8a5d051
Author: Michael Meissner <meissner@linux.ibm.com>
Date:   Thu Sep 11 20:03:53 2025 -0400

    Update ChangeLog.float

Diff:
---
 gcc/ChangeLog.float | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/gcc/ChangeLog.float b/gcc/ChangeLog.float
index 6d0a378fdf78..f0c3c849a85a 100644
--- a/gcc/ChangeLog.float
+++ b/gcc/ChangeLog.float
@@ -1,3 +1,34 @@
+==================== Branch work221-float, patch #312 ====================
+
+Update -mbfloat16 and -mieee16 support.
+
+2025-09-11  Michael Meissner  <meissner@linux.ibm.com>
+
+gcc/
+
+	* config/rs6000/altivec.md (altivec_vsplth_v8bf): New insn.
+	* config/rs6000/predicates.md (fp16_xxspltiw_constant): Rename insn, add
+	bfloat16 support.
+	* config/rs6000/rs6000-call.cc (USE_FP_FOR_ARG_P): Add bfloat16 support.
+	* config/rs6000/rs6000.cc (rs6000_hard_regno_mode_ok_uncached):
+	Likewise.
+	(rs6000_modes_tieable_p): Likewise.
+	(rs6000_debug_reg_global): Likewise.
+	(rs6000_setup_reg_addr_masks): Likewise.
+	(rs6000_init_hard_regno_mode_ok): Likewise.
+	(rs6000_secondary_reload_simple_move): Likewise.
+	(rs6000_preferred_reload_class): Likewise.
+	(rs6000_can_change_mode_class): Likewise.
+	(rs6000_function_value): Likewise.
+	(rs6000_scalar_mode_supported_p): Likewise.
+	(constant_fp_to_128bit_vector): Likewise.
+	(constant_generates_xxspltiw): Likewise.
+	* config/rs6000/rs6000.h (FP16_SCALAR_MODE_P): New macro.
+	* config/rs6000/rs6000.md (extendbf<mode>2): New insn.
+	(mov<mode>_xxspltiw): Add bfloat16 support.
+	* config/rs6000/vsx.md (vsx_xscvspdpn_sf): New insn.
+	(xvcvbf16spn_v8bf): Likewise.
+
 ==================== Branch work221-float, patch #311 ====================
 
 Add -mbfloat16 switch.