Always support float128 on ia64 (PR target/77586).

Bug 77586, and previously
<https://gcc.gnu.org/ml/gcc-bugs/2016-08/msg03233.html>, reports
ia64-elf failing to build because of float128_type_node being NULL,
but being used by the back end for __float128.

The global float128_type_node is only available conditionally, if
target hooks indicate TFmode is not only available as a scalar mode
and of the right format, but also supported in libgcc.  The back-end
support, however, expects the type always to be available for
__float128 even if the libgcc support is missing.

Although a target-specific node could be restored in the case where
libgcc support is missing, it seems better to address the missing
libgcc support.  Thus, this patch enables TFmode soft-fp in libgcc
globally for all ia64 targets.  Support for XFmode in libgcc (that is,
for libgcc2.c XFmode functions, not soft-fp) is also enabled for all
ia64 targets so that ia64 no longer needs to define the
TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P hook.

I've confirmed that ia64-elf builds cc1 with this patch and it passes
-fself-test.  I have not otherwise tested the patch.  It's plausible
that ia64-elf and ia64-freebsd might work as-is, but ia64-vms probably
needs further changes, by someone familiar with VMS shared libraries,
to implement an equivalent of ia64/t-softfp-compat in that case
(avoiding conflicts between __divtf3 from soft-fp and the old alias
for __divxf3).

	PR target/77586
gcc:
	* config/ia64/ia64.c (ia64_libgcc_floating_mode_supported_p)
	(TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P): Remove.
	* config/ia64/elf.h (IA64_NO_LIBGCC_TFMODE): Likewise.
	* config/ia64/freebsd.h (IA64_NO_LIBGCC_TFMODE): Likewise.
	* config/ia64/vms.h (IA64_NO_LIBGCC_XFMODE)
	(IA64_NO_LIBGCC_TFMODE): Likewise.

libgcc:
	* config.host (ia64*-*-elf*, ia64*-*-freebsd*, ia64-hp-*vms*): Use
	soft-fp.

From-SVN: r240955

5 files changed, 10 insertions, 42 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index cb33020..99e33a0 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2016-10-10  Joseph Myers  <joseph@codesourcery.com>
+
+	PR target/77586
+	* config/ia64/ia64.c (ia64_libgcc_floating_mode_supported_p)
+	(TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P): Remove.
+	* config/ia64/elf.h (IA64_NO_LIBGCC_TFMODE): Likewise.
+	* config/ia64/freebsd.h (IA64_NO_LIBGCC_TFMODE): Likewise.
+	* config/ia64/vms.h (IA64_NO_LIBGCC_XFMODE)
+	(IA64_NO_LIBGCC_TFMODE): Likewise.
+
 2016-10-11  Kugan Vivekanandarajah  <kuganv@linaro.org>
 
 	* tree-vrp.c (vrp_intersect_ranges_1): Allocate bitmap before
diff --git a/gcc/config/ia64/elf.h b/gcc/config/ia64/elf.h
index a65f3d8..633b5c9 100644
--- a/gcc/config/ia64/elf.h
+++ b/gcc/config/ia64/elf.h
@@ -65,6 +65,4 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 			  %{pg:gcrt0.o%s}%{!pg:%{p:mcrt0.o%s}%{!p:crt0.o%s}}}}\
 			crti.o%s crtbegin.o%s"
 
-#define IA64_NO_LIBGCC_TFMODE
-
 /* End of elf.h */
diff --git a/gcc/config/ia64/freebsd.h b/gcc/config/ia64/freebsd.h
index bcce09b..5d6784b 100644
--- a/gcc/config/ia64/freebsd.h
+++ b/gcc/config/ia64/freebsd.h
@@ -50,5 +50,3 @@ along with GCC; see the file COPYING3.  If not see
 #define TARGET_ELF		1
 
 #define JMP_BUF_SIZE  76
-
-#define IA64_NO_LIBGCC_TFMODE
diff --git a/gcc/config/ia64/ia64.c b/gcc/config/ia64/ia64.c
index d32823a..797b1b0 100644
--- a/gcc/config/ia64/ia64.c
+++ b/gcc/config/ia64/ia64.c
@@ -311,7 +311,6 @@ static rtx ia64_struct_value_rtx (tree, int);
 static tree ia64_gimplify_va_arg (tree, tree, gimple_seq *, gimple_seq *);
 static bool ia64_scalar_mode_supported_p (machine_mode mode);
 static bool ia64_vector_mode_supported_p (machine_mode mode);
-static bool ia64_libgcc_floating_mode_supported_p (machine_mode mode);
 static bool ia64_legitimate_constant_p (machine_mode, rtx);
 static bool ia64_legitimate_address_p (machine_mode, rtx, bool);
 static bool ia64_cannot_force_const_mem (machine_mode, rtx);
@@ -595,10 +594,6 @@ static const struct attribute_spec ia64_attribute_table[] =
 #undef TARGET_VECTOR_MODE_SUPPORTED_P
 #define TARGET_VECTOR_MODE_SUPPORTED_P ia64_vector_mode_supported_p
 
-#undef TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P
-#define TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P \
-  ia64_libgcc_floating_mode_supported_p
-
 #undef TARGET_LEGITIMATE_CONSTANT_P
 #define TARGET_LEGITIMATE_CONSTANT_P ia64_legitimate_constant_p
 #undef TARGET_LEGITIMATE_ADDRESS_P
@@ -11008,36 +11003,6 @@ ia64_vector_mode_supported_p (machine_mode mode)
     }
 }
 
-/* Implement TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P.  */
-
-static bool
-ia64_libgcc_floating_mode_supported_p (machine_mode mode)
-{
-  switch (mode)
-    {
-    case SFmode:
-    case DFmode:
-      return true;
-
-    case XFmode:
-#ifdef IA64_NO_LIBGCC_XFMODE
-      return false;
-#else
-      return true;
-#endif
-
-    case TFmode:
-#ifdef IA64_NO_LIBGCC_TFMODE
-      return false;
-#else
-      return true;
-#endif
-
-    default:
-      return false;
-    }
-}
-
 /* Implement the FUNCTION_PROFILER macro.  */
 
 void
diff --git a/gcc/config/ia64/vms.h b/gcc/config/ia64/vms.h
index 8a80a7e..21d36a5 100644
--- a/gcc/config/ia64/vms.h
+++ b/gcc/config/ia64/vms.h
@@ -154,6 +154,3 @@ STATIC func_ptr __CTOR_LIST__[1]                                             \
 /* Default values for _CRTL_VER and _VMS_VER.  */
 #define VMS_DEFAULT_CRTL_VER 80300000
 #define VMS_DEFAULT_VMS_VER 80300000
-
-#define IA64_NO_LIBGCC_XFMODE
-#define IA64_NO_LIBGCC_TFMODE