Add -mlong-double-128 for alpha

[Richard Henderson <rth at twiddle dot net>]

All the actual code to support this is present for Tru64, this
just lets me play with adding the GEM routines for Linux.


r~


        * config/alpha/alpha.h (MASK_LONG_DOUBLE_128): New.
        (TARGET_LONG_DOUBLE_128): New.
        (TARGET_SWITCHES): Add long-double-{128,64}.
        (TARGET_HAS_XFLOATING_LIBS): Default to TARGET_LONG_DOUBLE_128.
        (LONG_DOUBLE_TYPE_SIZE): Honor TARGET_LONG_DOUBLE_128.
        (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): New.
        (WIDEST_HARDWARE_FP_SIZE): New.
        (TARGET_CPU_CPP_BUILTINS): Define __LONG_DOUBLE_128__.
        * config/alpha/alpha.c (override_options): Clear MASK_LONG_DOUBLE_128
        if TARGET_VAX_FLOAT.
        * config/alpha/osf5.h (LONG_DOUBLE_TYPE_SIZE): Remove.
        (TARGET_DEFAULT): Set MASK_LONG_DOUBLE_128.

Index: alpha.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/alpha/alpha.c,v
retrieving revision 1.355
diff -c -p -d -u -r1.355 alpha.c
--- alpha.c	6 Mar 2004 18:33:33 -0000	1.355
+++ alpha.c	6 Mar 2004 18:38:31 -0000
@@ -390,6 +390,9 @@ override_options (void)
 	  warning ("trap mode not supported for VAX floats");
 	  alpha_fptm = ALPHA_FPTM_SU;
 	}
+      if (target_flags_explicit & MASK_LONG_DOUBLE_128)
+	warning ("128-bit long double not supported for VAX floats");
+      target_flags &= ~MASK_LONG_DOUBLE_128;
     }
 
   {
Index: alpha.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/alpha/alpha.h,v
retrieving revision 1.216
diff -c -p -d -u -r1.216 alpha.h
--- alpha.h	6 Feb 2004 06:18:21 -0000	1.216
+++ alpha.h	6 Mar 2004 18:38:32 -0000
@@ -67,6 +67,8 @@ Boston, MA 02111-1307, USA.  */
 	  builtin_define ("_IEEE_FP");			\
 	if (TARGET_IEEE_WITH_INEXACT)			\
 	  builtin_define ("_IEEE_FP_INEXACT");		\
+	if (TARGET_LONG_DOUBLE_128)			\
+	  builtin_define ("__LONG_DOUBLE_128__");	\
 							\
 	/* Macros dependent on the C dialect.  */	\
 	SUBTARGET_LANGUAGE_CPP_BUILTINS();		\
@@ -229,6 +231,11 @@ extern int alpha_tls_size;
 #define MASK_SMALL_TEXT (1 << 15)
 #define TARGET_SMALL_TEXT (target_flags & MASK_SMALL_TEXT)
 
+/* This means use IEEE quad-format for long double.  Assumes the 
+   presence of the GEM support library routines.  */
+#define MASK_LONG_DOUBLE_128 (1 << 16)
+#define TARGET_LONG_DOUBLE_128 (target_flags & MASK_LONG_DOUBLE_128)
+
 /* This means that the processor is an EV5, EV56, or PCA56.
    Unlike alpha_cpu this is not affected by -mtune= setting.  */
 #define MASK_CPU_EV5	(1 << 28)
@@ -261,7 +268,7 @@ extern int alpha_tls_size;
 #define TARGET_CAN_FAULT_IN_PROLOGUE 0
 #endif
 #ifndef TARGET_HAS_XFLOATING_LIBS
-#define TARGET_HAS_XFLOATING_LIBS 0
+#define TARGET_HAS_XFLOATING_LIBS TARGET_LONG_DOUBLE_128
 #endif
 #ifndef TARGET_PROFILING_NEEDS_GP
 #define TARGET_PROFILING_NEEDS_GP 0
@@ -322,6 +329,10 @@ extern int alpha_tls_size;
     {"large-text", -MASK_SMALL_TEXT, ""},				\
     {"tls-kernel", MASK_TLS_KERNEL,					\
      N_("Emit rdval instead of rduniq for thread pointer")},		\
+    {"long-double-128", MASK_LONG_DOUBLE_128,				\
+     N_("Use 128-bit long double")},					\
+    {"long-double-64", -MASK_LONG_DOUBLE_128,				\
+     N_("Use 64-bit long double")},					\
     {"", TARGET_DEFAULT | TARGET_CPU_DEFAULT				\
 	 | TARGET_DEFAULT_EXPLICIT_RELOCS, ""} }
 
@@ -438,7 +449,18 @@ extern const char *alpha_tls_size_string
 
 #define FLOAT_TYPE_SIZE 32
 #define DOUBLE_TYPE_SIZE 64
-#define LONG_DOUBLE_TYPE_SIZE 64
+#define LONG_DOUBLE_TYPE_SIZE (TARGET_LONG_DOUBLE_128 ? 128 : 64)
+
+/* Define this to set long double type size to use in libgcc2.c, which can
+   not depend on target_flags.  */
+#ifdef __LONG_DOUBLE_128__
+#define LIBGCC2_LONG_DOUBLE_TYPE_SIZE 128
+#else
+#define LIBGCC2_LONG_DOUBLE_TYPE_SIZE 64
+#endif
+
+/* Work around target_flags dependency in ada/targtyps.c.  */
+#define WIDEST_HARDWARE_FP_SIZE 64
 
 #define	WCHAR_TYPE "unsigned int"
 #define	WCHAR_TYPE_SIZE 32
Index: osf5.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/alpha/osf5.h,v
retrieving revision 1.9
diff -c -p -d -u -r1.9 osf5.h
--- osf5.h	27 Sep 2003 04:48:12 -0000	1.9
+++ osf5.h	6 Mar 2004 18:38:32 -0000
@@ -1,5 +1,5 @@
 /* Definitions of target machine for GNU compiler, for DEC Alpha on Tru64 5.
-   Copyright (C) 2000, 2001 Free Software Foundation, Inc.
+   Copyright (C) 2000, 2001, 2004 Free Software Foundation, Inc.
 
    This file is part of GCC.
 
@@ -19,11 +19,8 @@
    Boston, MA 02111-1307, USA.  */
 
 /* Tru64 5.1 uses IEEE QUAD format.  */
-/* ??? However, since there is no support for VAX H_floating, we must
-   drop back to a 64-bit long double to avoid a crash looking for the
-   format associated with TFmode.  */
-#undef LONG_DOUBLE_TYPE_SIZE
-#define LONG_DOUBLE_TYPE_SIZE  (TARGET_FLOAT_VAX ? 64 : 128)
+#undef TARGET_DEFAULT
+#define TARGET_DEFAULT	MASK_FP | MASK_FPREGS | MASK_LONG_DOUBLE_128
 
 /* In Tru64 UNIX V5.1, Compaq introduced a new assembler
    (/usr/lib/cmplrs/cc/adu) which currently (versions between 3.04.29 and