Hi,
Now that we've worked on -fexcess-precision, the comment in targhooks.c
no longer holds. We can now permit _Float16 on any target which provides
HFmode and supports HFmode in libgcc.
Bootstrapped and tested on x86-64, and in series on AArch64.
OK?
Thanks,
James
---
2016-09-30 James Greenhalgh <james.greenha...@arm.com>
* targhooks.c (default_floatn_mode): Enable _Float16 if a target
provides HFmode.
diff --git a/gcc/targhooks.c b/gcc/targhooks.c
index 08d0b35..bf94b2a 100644
--- a/gcc/targhooks.c
+++ b/gcc/targhooks.c
@@ -513,10 +513,12 @@ default_floatn_mode (int n, bool extended)
switch (n)
{
case 16:
- /* We do not use HFmode for _Float16 by default because the
- required excess precision support is not present and the
- interactions with promotion of the older __fp16 need to
- be worked out. */
+ /* Always enable _Float16 if we have basic support for the mode.
+ Targets can control the range and precision of operations on
+ the _Float16 type using TARGET_C_EXCESS_PRECISION. */
+#ifdef HAVE_HFmode
+ cand = HFmode;
+#endif
break;
case 32:
