This patch is the first in a series of patches that will eventually add support
for IEEE 128-bit floating point support to the PowerPC GCC compiler. At the
current time, we do not plan to change the default for long double. I added a
new type keyword (__float128) to get access to IEEE 128-bit floating point, and
another (__ibm128) to get access to IBM extended double type.
Until all of the GCC and LIBGCC patches have been committed, you will not be
able to use IEEE 128-bit floating point, and -mfloat128-software will not be
turned on by default.
This patch adds the new modes (KFmode and IFmode) and the switches
(-mfloat128-{none,software}).
Due to the fact that TFmode in the PowerPC compiler either represents IEEE
128-bit floating point or the IBM extended double (double-double) format. For
most PowerPC users, the default is to use IBM extended double for long double.
Because TFmode can be either floating point format, I added new new modes:
KFmode -- IEEE 128-bit floating point
IFmode -- IBM extended double floating point
If the default for TFmode is ibm extended double, the port will eventually use
KFmode for IEEE 128-bit floating point. Likewise if the default for TFmode is
IEEE 128-bit floating point, the port will use TFmode for IEEE 128-bit floating
point, and IFmode for IBM extended double.
I have bootstraped these patches on a power7 and compared them to the unpatched
compiler. There were no changes when running make check. Are these patches ok
to install in the trunk?
2015-05-22 Michael Meissner <[email protected]>
* config/rs6000/rs6000-modes.def (IFmode): Define IFmode to
provide access to the IBM extended double floating point mode if
long double is IEEE 128-bit floating point.
(KFmode): Define KFmode to provide access to IEEE 128-bit floating
point if long double is the IBM extended double type.
* config/rs6000/rs6000.opt (-mfloat128-none): New switches to
enable adding IEEE 128-bit floating point support.
(-mfloat128-software): Likewise.
(-mfloat128-sw): Likewise.
* config/rs6000/rs6000.c (rs6000_hard_regno_mode_ok): Do not allow
128-bit floating point types to occupy any register if
-mlong-double-64. Do not allow use of IFmode/KFmode unless
-mfloat128-software is enabled.
(rs6000_debug_reg_global): Add IEEE 128-bit floating point debug
support.
(rs6000_option_override_internal): Add -mfloat128-* support.
(rs6000_init_builtins): Setup __ibm128 and __float128 type modes.
* config/rs6000/rs6000.h (rs6000_builtin_type_index): Add ibm128
and float128 type nodes.
(ieee128_float_type_node): Likewise.
(ibm128_float_type_node): Likewise.
--
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: [email protected], phone: +1 (978) 899-4797
Index: gcc/config/rs6000/rs6000-modes.def
===================================================================
--- gcc/config/rs6000/rs6000-modes.def (revision 223458)
+++ gcc/config/rs6000/rs6000-modes.def (working copy)
@@ -18,6 +18,13 @@
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
+/* IBM 128-bit floating point. IFmode and KFmode use the fractional float
+ support in order to declare 3 128-bit floating point types. */
+FRACTIONAL_FLOAT_MODE (IF, 106, 16, ibm_extended_format);
+
+/* Explicit IEEE 128-bit floating point. */
+FRACTIONAL_FLOAT_MODE (KF, 113, 16, ieee_quad_format);
+
/* 128-bit floating point. ABI_V4 uses IEEE quad, AIX/Darwin
adjust this in rs6000_option_override_internal. */
FLOAT_MODE (TF, 16, ieee_quad_format);
Index: gcc/config/rs6000/rs6000.opt
===================================================================
--- gcc/config/rs6000/rs6000.opt (revision 223458)
+++ gcc/config/rs6000/rs6000.opt (working copy)
@@ -600,3 +600,19 @@ Allow float/double variables in upper re
moptimize-swaps
Target Undocumented Var(rs6000_optimize_swaps) Init(1) Save
Analyze and remove doubleword swaps from VSX computations.
+
+mfloat128-
+Target RejectNegative Joined Enum(float128_type_t) Var(TARGET_FLOAT128)
Init(FLOAT128_UNSET) Save
+-mfloat128-{software,none} - Specify how IEEE 128-bit floating point is used.
+
+Enum
+Name(float128_type_t) Type(enum float128_type_t)
+
+EnumValue
+Enum(float128_type_t) String(none) Value(FLOAT128_NONE)
+
+EnumValue
+Enum(float128_type_t) String(software) Value(FLOAT128_SW)
+
+EnumValue
+Enum(float128_type_t) String(sw) Value(FLOAT128_SW)
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c (revision 223458)
+++ gcc/config/rs6000/rs6000.c (working copy)
@@ -1817,6 +1817,16 @@ rs6000_hard_regno_mode_ok (int regno, ma
&& IN_RANGE (last_regno, FIRST_GPR_REGNO, LAST_GPR_REGNO)
&& ((regno & 1) == 0));
+ /* If we don't allow 128-bit binary floating point, disallow the 128-bit
+ types from going in any registers. Similarly if __float128 is not
+ supported, don't allow __float128/__ibm128 types. */
+ if (!TARGET_LONG_DOUBLE_128
+ && (mode == TFmode || mode == KFmode || mode == IFmode))
+ return false;
+
+ if (!TARGET_FLOAT128 && (mode == KFmode || mode == IFmode))
+ return false;
+
/* VSX registers that overlap the FPR registers are larger than for non-VSX
implementations. Don't allow an item to be split between a FP register
and an Altivec register. Allow TImode in all VSX registers if the user
@@ -2086,6 +2096,7 @@ rs6000_debug_reg_global (void)
const char *trace_str;
const char *abi_str;
const char *cmodel_str;
+ const char *float128_str;
struct cl_target_option cl_opts;
/* Modes we want tieable information on. */
@@ -2099,6 +2110,8 @@ rs6000_debug_reg_global (void)
SFmode,
DFmode,
TFmode,
+ IFmode,
+ KFmode,
SDmode,
DDmode,
TDmode,
@@ -2445,6 +2458,15 @@ rs6000_debug_reg_global (void)
fprintf (stderr, DEBUG_FMT_S, "e500_double",
(TARGET_E500_DOUBLE ? "true" : "false"));
+ switch (TARGET_FLOAT128)
+ {
+ case FLOAT128_NONE: float128_str = "none"; break;
+ case FLOAT128_SW: float128_str = "software"; break;
+ default: float128_str = "unknown"; break;
+ }
+
+ fprintf (stderr, DEBUG_FMT_S, "float128", float128_str);
+
if (TARGET_LINK_STACK)
fprintf (stderr, DEBUG_FMT_S, "link_stack", "true");
@@ -3703,6 +3725,13 @@ rs6000_option_override_internal (bool gl
&& optimize >= 3)
rs6000_isa_flags |= OPTION_MASK_P8_FUSION_SIGN;
+ /* Set the appropriate IEEE 128-bit floating option. Do not enable float128
+ support by default until the libgcc support is added. */
+ if (TARGET_FLOAT128 == FLOAT128_UNSET)
+ TARGET_FLOAT128 = FLOAT128_NONE;
+ else if (TARGET_FLOAT128 == FLOAT128_SW && !TARGET_VSX)
+ error ("-mfloat128-software requires VSX support");
+
if (TARGET_DEBUG_REG || TARGET_DEBUG_TARGET)
rs6000_print_isa_options (stderr, 0, "after defaults", rs6000_isa_flags);
@@ -14320,6 +14349,8 @@ rs6000_init_builtins (void)
tree tdecl;
tree ftype;
machine_mode mode;
+ machine_mode ieee128_mode;
+ machine_mode ibm128_mode;
if (TARGET_DEBUG_BUILTIN)
fprintf (stderr, "rs6000_init_builtins%s%s%s%s\n",
@@ -14387,6 +14418,32 @@ rs6000_init_builtins (void)
dfloat128_type_internal_node = dfloat128_type_node;
void_type_internal_node = void_type_node;
+ /* 128-bit floating point support. KFmode is IEEE 128-bit floating point.
+ IFmode is the IBM extended 128-bit format that is a pair of doubles.
+ TFmode will be either IEEE 128-bit floating point or the IBM double-double
+ format that uses a pair of doubles, depending on the switches and
+ defaults. */
+ if (TARGET_IEEEQUAD)
+ {
+ ieee128_mode = TFmode;
+ ibm128_mode = IFmode;
+ }
+ else
+ {
+ ieee128_mode = KFmode;
+ ibm128_mode = TFmode;
+ }
+
+ ieee128_float_type_node = make_node (REAL_TYPE);
+ TYPE_PRECISION (ieee128_float_type_node) = 128;
+ layout_type (ieee128_float_type_node);
+ SET_TYPE_MODE (ieee128_float_type_node, ieee128_mode);
+
+ ibm128_float_type_node = make_node (REAL_TYPE);
+ TYPE_PRECISION (ibm128_float_type_node) = 128;
+ layout_type (ibm128_float_type_node);
+ SET_TYPE_MODE (ibm128_float_type_node, ibm128_mode);
+
/* Initialize the modes for builtin_function_type, mapping a machine mode to
tree type node. */
builtin_mode_to_type[QImode][0] = integer_type_node;
@@ -14399,6 +14456,8 @@ rs6000_init_builtins (void)
builtin_mode_to_type[TImode][1] = unsigned_intTI_type_node;
builtin_mode_to_type[SFmode][0] = float_type_node;
builtin_mode_to_type[DFmode][0] = double_type_node;
+ builtin_mode_to_type[IFmode][0] = ibm128_float_type_node;
+ builtin_mode_to_type[KFmode][0] = ieee128_float_type_node;
builtin_mode_to_type[TFmode][0] = long_double_type_node;
builtin_mode_to_type[DDmode][0] = dfloat64_type_node;
builtin_mode_to_type[TDmode][0] = dfloat128_type_node;
Index: gcc/config/rs6000/rs6000.h
===================================================================
--- gcc/config/rs6000/rs6000.h (revision 223458)
+++ gcc/config/rs6000/rs6000.h (working copy)
@@ -2715,6 +2715,8 @@ enum rs6000_builtin_type_index
RS6000_BTI_dfloat64, /* dfloat64_type_node */
RS6000_BTI_dfloat128, /* dfloat128_type_node */
RS6000_BTI_void, /* void_type_node */
+ RS6000_BTI_ieee128_float, /* ieee 128-bit floating point */
+ RS6000_BTI_ibm128_float, /* IBM 128-bit floating point */
RS6000_BTI_MAX
};
@@ -2769,6 +2771,8 @@ enum rs6000_builtin_type_index
#define dfloat64_type_internal_node
(rs6000_builtin_types[RS6000_BTI_dfloat64])
#define dfloat128_type_internal_node
(rs6000_builtin_types[RS6000_BTI_dfloat128])
#define void_type_internal_node
(rs6000_builtin_types[RS6000_BTI_void])
+#define ieee128_float_type_node
(rs6000_builtin_types[RS6000_BTI_ieee128_float])
+#define ibm128_float_type_node
(rs6000_builtin_types[RS6000_BTI_ibm128_float])
extern GTY(()) tree rs6000_builtin_types[RS6000_BTI_MAX];
extern GTY(()) tree rs6000_builtin_decls[RS6000_BUILTIN_COUNT];
Index: gcc/config/rs6000/rs6000-opts.h
===================================================================
--- gcc/config/rs6000/rs6000-opts.h (revision 223458)
+++ gcc/config/rs6000/rs6000-opts.h (working copy)
@@ -79,6 +79,15 @@ enum fpu_type_t
FPU_DF_FULL /* Full Double Single Precision FPU */
};
+
+/* Float128 support. */
+enum float128_type_t
+{
+ FLOAT128_UNSET = -1, /* Initial value. */
+ FLOAT128_NONE, /* No __float128 support. */
+ FLOAT128_SW /* software __float128 support. */
+};
+
/* Types of costly dependences. */
enum rs6000_dependence_cost
{
