gcc/ada/ChangeLog:
* gcc-interface/misc.c (gnat_post_options): Issue an error for
-fexcess-precision=16.
gcc/c-family/ChangeLog:
* c-common.c (excess_precision_mode_join): Update below comments.
(c_ts18661_flt_eval_method): Set excess_precision_type to
EXCESS_PRECISION_TYPE_FLOAT16 when -fexcess-precision=16.
* c-cppbuiltin.c (cpp_atomic_builtins): Update below comments.
(c_cpp_flt_eval_method_iec_559): Set excess_precision_type to
EXCESS_PRECISION_TYPE_FLOAT16 when -fexcess-precision=16.
gcc/ChangeLog:
* common.opt: Support -fexcess-precision=16.
* config/aarch64/aarch64.c (aarch64_excess_precision): Return
FLT_EVAL_METHOD_PROMOTE_TO_FLOAT16 when
EXCESS_PRECISION_TYPE_FLOAT16.
* config/arm/arm.c (arm_excess_precision): Ditto.
* config/i386/i386.c (ix86_get_excess_precision): Ditto.
* config/m68k/m68k.c (m68k_excess_precision): Issue an error
when EXCESS_PRECISION_TYPE_FLOAT16.
* config/s390/s390.c (s390_excess_precision): Ditto.
* coretypes.h (enum excess_precision_type): Add
EXCESS_PRECISION_TYPE_FLOAT16.
* doc/tm.texi (TARGET_C_EXCESS_PRECISION): Update documents.
* doc/tm.texi.in (TARGET_C_EXCESS_PRECISION): Ditto.
* doc/extend.texi (Half-Precision): Document
-fexcess-precision=16.
* flag-types.h (enum excess_precision): Add
EXCESS_PRECISION_FLOAT16.
* target.def (excess_precision): Update document.
* tree.c (excess_precision_type): Set excess_precision_type to
EXCESS_PRECISION_FLOAT16 when -fexcess-precision=16.
gcc/fortran/ChangeLog:
* options.c (gfc_post_options): Issue an error for
-fexcess-precision=16.
gcc/testsuite/ChangeLog:
* gcc.target/i386/float16-6.c: New test.
---
gcc/ada/gcc-interface/misc.c | 3 +++
gcc/c-family/c-common.c | 6 ++++--
gcc/c-family/c-cppbuiltin.c | 6 ++++--
gcc/common.opt | 5 ++++-
gcc/config/aarch64/aarch64.c | 1 +
gcc/config/arm/arm.c | 1 +
gcc/config/i386/i386.c | 2 ++
gcc/config/m68k/m68k.c | 2 ++
gcc/config/s390/s390.c | 2 ++
gcc/coretypes.h | 3 ++-
gcc/doc/extend.texi | 3 ++-
gcc/doc/tm.texi | 14 ++++++++++----
gcc/doc/tm.texi.in | 3 +++
gcc/flag-types.h | 3 ++-
gcc/fortran/options.c | 3 +++
gcc/target.def | 11 +++++++----
gcc/testsuite/gcc.target/i386/float16-6.c | 8 ++++++++
gcc/tree.c | 3 ++-
18 files changed, 62 insertions(+), 17 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/float16-6.c
diff --git a/gcc/ada/gcc-interface/misc.c b/gcc/ada/gcc-interface/misc.c
index 186367ac6d1..96199bd4b63 100644
--- a/gcc/ada/gcc-interface/misc.c
+++ b/gcc/ada/gcc-interface/misc.c
@@ -256,6 +256,9 @@ gnat_post_options (const char **pfilename ATTRIBUTE_UNUSED)
/* Excess precision other than "fast" requires front-end support. */
if (flag_excess_precision == EXCESS_PRECISION_STANDARD)
sorry ("%<-fexcess-precision=standard%> for Ada");
+ else if (flag_excess_precision == EXCESS_PRECISION_FLOAT16)
+ sorry ("%<-fexcess-precision=16%> for Ada");
+
flag_excess_precision = EXCESS_PRECISION_FAST;
/* No psABI change warnings for Ada. */
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index aacdfb46a02..7e72062c77c 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -8772,7 +8772,7 @@ excess_precision_mode_join (enum flt_eval_method x,
This relates to the effective excess precision seen by the user,
which is the join point of the precision the target requests for
- -fexcess-precision={standard,fast} and the implicit excess precision
+ -fexcess-precision={standard,fast,16} and the implicit excess precision
the target uses. */
static enum flt_eval_method
@@ -8784,7 +8784,9 @@ c_ts18661_flt_eval_method (void)
enum excess_precision_type flag_type
= (flag_excess_precision == EXCESS_PRECISION_STANDARD
? EXCESS_PRECISION_TYPE_STANDARD
- : EXCESS_PRECISION_TYPE_FAST);
+ : (flag_excess_precision == EXCESS_PRECISION_FLOAT16
+ ? EXCESS_PRECISION_TYPE_FLOAT16
+ : EXCESS_PRECISION_TYPE_FAST));
enum flt_eval_method requested
= targetm.c.excess_precision (flag_type);
diff --git a/gcc/c-family/c-cppbuiltin.c b/gcc/c-family/c-cppbuiltin.c
index f79f939bd10..5f30354a33c 100644
--- a/gcc/c-family/c-cppbuiltin.c
+++ b/gcc/c-family/c-cppbuiltin.c
@@ -753,7 +753,7 @@ cpp_atomic_builtins (cpp_reader *pfile)
/* Return TRUE if the implicit excess precision in which the back-end will
compute floating-point calculations is not more than the explicit
excess precision that the front-end will apply under
- -fexcess-precision=[standard|fast].
+ -fexcess-precision=[standard|fast|16].
More intuitively, return TRUE if the excess precision proposed by the
front-end is the excess precision that will actually be used. */
@@ -764,7 +764,9 @@ c_cpp_flt_eval_method_iec_559 (void)
enum excess_precision_type front_end_ept
= (flag_excess_precision == EXCESS_PRECISION_STANDARD
? EXCESS_PRECISION_TYPE_STANDARD
- : EXCESS_PRECISION_TYPE_FAST);
+ : (flag_excess_precision == EXCESS_PRECISION_FLOAT16
+ ? EXCESS_PRECISION_TYPE_FLOAT16
+ : EXCESS_PRECISION_TYPE_FAST));
enum flt_eval_method back_end
= targetm.c.excess_precision (EXCESS_PRECISION_TYPE_IMPLICIT);
diff --git a/gcc/common.opt b/gcc/common.opt
index d9da1131eda..3dd74766400 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1518,7 +1518,7 @@ Perform a number of minor, expensive optimizations.
fexcess-precision=
Common Joined RejectNegative Enum(excess_precision) Var(flag_excess_precision)
Init(EXCESS_PRECISION_DEFAULT) Optimization SetByCombined
--fexcess-precision=[fast|standard] Specify handling of excess
floating-point precision.
+-fexcess-precision=[fast|standard|16] Specify handling of excess
floating-point precision.
Enum
Name(excess_precision) Type(enum excess_precision) UnknownError(unknown excess
precision style %qs)
@@ -1529,6 +1529,9 @@ Enum(excess_precision) String(fast)
Value(EXCESS_PRECISION_FAST)
EnumValue
Enum(excess_precision) String(standard) Value(EXCESS_PRECISION_STANDARD)
+EnumValue
+Enum(excess_precision) String(16) Value(EXCESS_PRECISION_FLOAT16)
+
; Whether we permit the extended set of values for FLT_EVAL_METHOD
; introduced in ISO/IEC TS 18661-3, or limit ourselves to those in C99/C11.
fpermitted-flt-eval-methods=
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 3bdf19d71b5..c986a93a243 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -24797,6 +24797,7 @@ aarch64_excess_precision (enum excess_precision_type
type)
? FLT_EVAL_METHOD_PROMOTE_TO_FLOAT16
: FLT_EVAL_METHOD_PROMOTE_TO_FLOAT);
case EXCESS_PRECISION_TYPE_IMPLICIT:
+ case EXCESS_PRECISION_TYPE_FLOAT16:
return FLT_EVAL_METHOD_PROMOTE_TO_FLOAT16;
default:
gcc_unreachable ();
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 6d781e23ee9..e2a18615860 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -25599,6 +25599,7 @@ arm_excess_precision (enum excess_precision_type type)
? FLT_EVAL_METHOD_PROMOTE_TO_FLOAT16
: FLT_EVAL_METHOD_PROMOTE_TO_FLOAT);
case EXCESS_PRECISION_TYPE_IMPLICIT:
+ case EXCESS_PRECISION_TYPE_FLOAT16:
return FLT_EVAL_METHOD_PROMOTE_TO_FLOAT16;
default:
gcc_unreachable ();
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 7979e240426..dc673c89bc8 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -23352,6 +23352,8 @@ ix86_get_excess_precision (enum excess_precision_type
type)
return (type == EXCESS_PRECISION_TYPE_STANDARD
? FLT_EVAL_METHOD_PROMOTE_TO_FLOAT
: FLT_EVAL_METHOD_UNPREDICTABLE);
+ case EXCESS_PRECISION_TYPE_FLOAT16:
+ return FLT_EVAL_METHOD_PROMOTE_TO_FLOAT16;
default:
gcc_unreachable ();
}
diff --git a/gcc/config/m68k/m68k.c b/gcc/config/m68k/m68k.c
index 3f63c60fa92..2fef457c09e 100644
--- a/gcc/config/m68k/m68k.c
+++ b/gcc/config/m68k/m68k.c
@@ -7115,6 +7115,8 @@ m68k_excess_precision (enum excess_precision_type type)
return FLT_EVAL_METHOD_PROMOTE_TO_FLOAT;
return FLT_EVAL_METHOD_PROMOTE_TO_LONG_DOUBLE;
+ case EXCESS_PRECISION_TYPE_FLOAT16:
+ error ("%<-fexcess-precision=16%> is not supported on this target");
default:
gcc_unreachable ();
}
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index b1d3b99784d..234ee4ac9c4 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -16515,6 +16515,8 @@ s390_excess_precision (enum excess_precision_type type)
ensure consistency with the implementation in glibc, report that
float is evaluated to the range and precision of double. */
return FLT_EVAL_METHOD_PROMOTE_TO_DOUBLE;
+ case EXCESS_PRECISION_TYPE_FLOAT16:
+ error ("%<-fexcess-precision=16%> is not supported on this target");
default:
gcc_unreachable ();
}
diff --git a/gcc/coretypes.h b/gcc/coretypes.h
index 406572e947d..07b9aa656c5 100644
--- a/gcc/coretypes.h
+++ b/gcc/coretypes.h
@@ -424,7 +424,8 @@ enum excess_precision_type
{
EXCESS_PRECISION_TYPE_IMPLICIT,
EXCESS_PRECISION_TYPE_STANDARD,
- EXCESS_PRECISION_TYPE_FAST
+ EXCESS_PRECISION_TYPE_FAST,
+ EXCESS_PRECISION_TYPE_FLOAT16
};
/* Level of size optimization. */
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index f42fd633725..3a1978efc97 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -1161,7 +1161,8 @@ operations will be emulated by software emulation and the
@code{float}
instructions. The default behavior for @code{FLT_EVAL_METHOD} is to keep
the intermediate result of the operation as 32-bit precision. This may lead
to inconsistent behavior between software emulation and AVX512-FP16
-instructions.
+instructions. Using @option{-fexcess-precision=16} and will force round
+back after each operation.
@node Decimal Float
@section Decimal Floating Types
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index c8f4abe3e41..9fac173a217 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -982,20 +982,26 @@ Do not define this macro if it would never modify @var{m}.
Return a value, with the same meaning as the C99 macro
@code{FLT_EVAL_METHOD} that describes which excess precision should be
applied. @var{type} is either @code{EXCESS_PRECISION_TYPE_IMPLICIT},
-@code{EXCESS_PRECISION_TYPE_FAST}, or
-@code{EXCESS_PRECISION_TYPE_STANDARD}. For
+@code{EXCESS_PRECISION_TYPE_FAST},
+@code{EXCESS_PRECISION_TYPE_STANDARD}, or
+@code{EXCESS_PRECISION_TYPE_FLOAT16}. For
@code{EXCESS_PRECISION_TYPE_IMPLICIT}, the target should return which
precision and range operations will be implictly evaluated in regardless
of the excess precision explicitly added. For
-@code{EXCESS_PRECISION_TYPE_STANDARD} and
+@code{EXCESS_PRECISION_TYPE_STANDARD},
+@code{EXCESS_PRECISION_TYPE_FLOAT16}, and
@code{EXCESS_PRECISION_TYPE_FAST}, the target should return the
explicit excess precision that should be added depending on the
value set for @option{-fexcess-precision=@r{[}standard@r{|}fast@r{]}}.
Note that unpredictable explicit excess precision does not make sense,
so a target should never return @code{FLT_EVAL_METHOD_UNPREDICTABLE}
-when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD} or
+when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD},
+@code{EXCESS_PRECISION_TYPE_FLOAT16} or
@code{EXCESS_PRECISION_TYPE_FAST}.
@end deftypefn
+Return a value, with the same meaning as the C99 macro
+@code{FLT_EVAL_METHOD} that describes which excess precision should be
+applied.
@deftypefn {Target Hook} machine_mode TARGET_PROMOTE_FUNCTION_MODE (const_tree
@var{type}, machine_mode @var{mode}, int *@var{punsignedp}, const_tree
@var{funtype}, int @var{for_return})
Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index 9c4b5016053..90a8d790758 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -929,6 +929,9 @@ Do not define this macro if it would never modify @var{m}.
@end defmac
@hook TARGET_C_EXCESS_PRECISION
+Return a value, with the same meaning as the C99 macro
+@code{FLT_EVAL_METHOD} that describes which excess precision should be
+applied.
@hook TARGET_PROMOTE_FUNCTION_MODE
diff --git a/gcc/flag-types.h b/gcc/flag-types.h
index e43d1de490d..5eeb5046222 100644
--- a/gcc/flag-types.h
+++ b/gcc/flag-types.h
@@ -198,7 +198,8 @@ enum excess_precision
{
EXCESS_PRECISION_DEFAULT,
EXCESS_PRECISION_FAST,
- EXCESS_PRECISION_STANDARD
+ EXCESS_PRECISION_STANDARD,
+ EXCESS_PRECISION_FLOAT16
};
/* The options for which values of FLT_EVAL_METHOD are permissible. */
diff --git a/gcc/fortran/options.c b/gcc/fortran/options.c
index 1723f689a57..847e20e8829 100644
--- a/gcc/fortran/options.c
+++ b/gcc/fortran/options.c
@@ -267,6 +267,9 @@ gfc_post_options (const char **pfilename)
support. */
if (flag_excess_precision == EXCESS_PRECISION_STANDARD)
sorry ("%<-fexcess-precision=standard%> for Fortran");
+ else if (flag_excess_precision == EXCESS_PRECISION_FLOAT16)
+ sorry ("%<-fexcess-precision=16%> for Fortran");
+
flag_excess_precision = EXCESS_PRECISION_FAST;
/* Fortran allows associative math - but we cannot reassociate if
diff --git a/gcc/target.def b/gcc/target.def
index 2e40448e6c5..b0bd79a0671 100644
--- a/gcc/target.def
+++ b/gcc/target.def
@@ -6192,18 +6192,21 @@ DEFHOOK
"Return a value, with the same meaning as the C99 macro\n\
@code{FLT_EVAL_METHOD} that describes which excess precision should be\n\
applied. @var{type} is either @code{EXCESS_PRECISION_TYPE_IMPLICIT},\n\
-@code{EXCESS_PRECISION_TYPE_FAST}, or\n\
-@code{EXCESS_PRECISION_TYPE_STANDARD}. For\n\
+@code{EXCESS_PRECISION_TYPE_FAST},\n\
+@code{EXCESS_PRECISION_TYPE_STANDARD}, or\n\
+@code{EXCESS_PRECISION_TYPE_FLOAT16}. For\n\
@code{EXCESS_PRECISION_TYPE_IMPLICIT}, the target should return which\n\
precision and range operations will be implictly evaluated in regardless\n\
of the excess precision explicitly added. For\n\
-@code{EXCESS_PRECISION_TYPE_STANDARD} and\n\
+@code{EXCESS_PRECISION_TYPE_STANDARD}, \n\
+@code{EXCESS_PRECISION_TYPE_FLOAT16}, and\n\
@code{EXCESS_PRECISION_TYPE_FAST}, the target should return the\n\
explicit excess precision that should be added depending on the\n\
value set for @option{-fexcess-precision=@r{[}standard@r{|}fast@r{]}}.\n\
Note that unpredictable explicit excess precision does not make sense,\n\
so a target should never return @code{FLT_EVAL_METHOD_UNPREDICTABLE}\n\
-when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD} or\n\
+when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD},\n\
+@code{EXCESS_PRECISION_TYPE_FLOAT16} or\n\
@code{EXCESS_PRECISION_TYPE_FAST}.",
enum flt_eval_method, (enum excess_precision_type type),
default_excess_precision)
diff --git a/gcc/testsuite/gcc.target/i386/float16-6.c
b/gcc/testsuite/gcc.target/i386/float16-6.c
new file mode 100644
index 00000000000..599f4495086
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/float16-6.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-msse2 -O2 -fdump-tree-gimple -fexcess-precision=16" } */
+/* { dg-final { scan-tree-dump-not "\\(float\\)" "gimple" } } */
+_Float16
+foo (_Float16 a, _Float16 b, _Float16 c)
+{
+ return a + b + c;
+}
diff --git a/gcc/tree.c b/gcc/tree.c
index bead1ac134c..20dfbe00b88 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -7633,7 +7633,8 @@ excess_precision_type (tree type)
enum excess_precision_type requested_type
= (flag_excess_precision == EXCESS_PRECISION_FAST
? EXCESS_PRECISION_TYPE_FAST
- : EXCESS_PRECISION_TYPE_STANDARD);
+ : (flag_excess_precision == EXCESS_PRECISION_FLOAT16
+ ? EXCESS_PRECISION_TYPE_FLOAT16 :EXCESS_PRECISION_TYPE_STANDARD));
enum flt_eval_method target_flt_eval_method
= targetm.c.excess_precision (requested_type);
--
2.27.0
