r352221 - Disable _Float16 for non ARM/SPIR Targets
Erich Keane via cfe-commits
cfe-commits at lists.llvm.org
Fri Jan 25 09:27:58 PST 2019
Author: erichkeane
Date: Fri Jan 25 09:27:57 2019
New Revision: 352221
URL: http://llvm.org/viewvc/llvm-project?rev=352221&view=rev
Log:
Disable _Float16 for non ARM/SPIR Targets
As Discussed here:
http://lists.llvm.org/pipermail/llvm-dev/2019-January/129543.html
There are problems exposing the _Float16 type on architectures that
haven't defined the ABI/ISel for the type yet, so we're temporarily
disabling the type and making it opt-in.
Differential Revision: https://reviews.llvm.org/D57188
Change-Id: I5db7366dedf1deb9485adb8948b1deb7e612a736
Added:
cfe/trunk/test/Sema/Float16.c (with props)
Modified:
cfe/trunk/docs/LanguageExtensions.rst
cfe/trunk/include/clang/Basic/TargetInfo.h
cfe/trunk/lib/Basic/TargetInfo.cpp
cfe/trunk/lib/Basic/Targets/AArch64.cpp
cfe/trunk/lib/Basic/Targets/ARM.cpp
cfe/trunk/lib/Basic/Targets/SPIR.h
cfe/trunk/lib/Sema/SemaType.cpp
cfe/trunk/test/AST/float16.cpp
cfe/trunk/test/CodeGenCXX/float16-declarations.cpp
cfe/trunk/test/CodeGenCXX/mangle-ms.cpp
cfe/trunk/test/Lexer/half-literal.cpp
Modified: cfe/trunk/docs/LanguageExtensions.rst
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/LanguageExtensions.rst?rev=352221&r1=352220&r2=352221&view=diff
==============================================================================
--- cfe/trunk/docs/LanguageExtensions.rst (original)
+++ cfe/trunk/docs/LanguageExtensions.rst Fri Jan 25 09:27:57 2019
@@ -474,44 +474,58 @@ Half-Precision Floating Point
=============================
Clang supports two half-precision (16-bit) floating point types: ``__fp16`` and
-``_Float16``. ``__fp16`` is defined in the ARM C Language Extensions (`ACLE
-<http://infocenter.arm.com/help/topic/com.arm.doc.ihi0053d/IHI0053D_acle_2_1.pdf>`_)
-and ``_Float16`` in ISO/IEC TS 18661-3:2015.
-
-``__fp16`` is a storage and interchange format only. This means that values of
-``__fp16`` promote to (at least) float when used in arithmetic operations.
-There are two ``__fp16`` formats. Clang supports the IEEE 754-2008 format and
-not the ARM alternative format.
-
-ISO/IEC TS 18661-3:2015 defines C support for additional floating point types.
-``_FloatN`` is defined as a binary floating type, where the N suffix denotes
-the number of bits and is 16, 32, 64, or greater and equal to 128 and a
-multiple of 32. Clang supports ``_Float16``. The difference from ``__fp16`` is
-that arithmetic on ``_Float16`` is performed in half-precision, thus it is not
-a storage-only format. ``_Float16`` is available as a source language type in
-both C and C++ mode.
-
-It is recommended that portable code use the ``_Float16`` type because
-``__fp16`` is an ARM C-Language Extension (ACLE), whereas ``_Float16`` is
-defined by the C standards committee, so using ``_Float16`` will not prevent
-code from being ported to architectures other than Arm. Also, ``_Float16``
-arithmetic and operations will directly map on half-precision instructions when
-they are available (e.g. Armv8.2-A), avoiding conversions to/from
-single-precision, and thus will result in more performant code. If
-half-precision instructions are unavailable, values will be promoted to
-single-precision, similar to the semantics of ``__fp16`` except that the
-results will be stored in single-precision.
-
-In an arithmetic operation where one operand is of ``__fp16`` type and the
-other is of ``_Float16`` type, the ``_Float16`` type is first converted to
-``__fp16`` type and then the operation is completed as if both operands were of
-``__fp16`` type.
-
-To define a ``_Float16`` literal, suffix ``f16`` can be appended to the compile-time
-constant declaration. There is no default argument promotion for ``_Float16``; this
-applies to the standard floating types only. As a consequence, for example, an
-explicit cast is required for printing a ``_Float16`` value (there is no string
-format specifier for ``_Float16``).
+``_Float16``. These types are supported in all language modes.
+
+``__fp16`` is supported on every target, as it is purely a storage format; see below.
+``_Float16`` is currently only supported on the following targets, with further
+targets pending ABI standardization:
+- 32-bit ARM
+- 64-bit ARM (AArch64)
+- SPIR
+``_Float16`` will be supported on more targets as they define ABIs for it.
+
+``__fp16`` is a storage and interchange format only. This means that values of
+``__fp16`` are immediately promoted to (at least) ``float`` when used in arithmetic
+operations, so that e.g. the result of adding two ``__fp16`` values has type ``float``.
+The behavior of ``__fp16`` is specified by the ARM C Language Extensions (`ACLE <http://infocenter.arm.com/help/topic/com.arm.doc.ihi0053d/IHI0053D_acle_2_1.pdf>`_).
+Clang uses the ``binary16`` format from IEEE 754-2008 for ``__fp16``, not the ARM
+alternative format.
+
+``_Float16`` is an extended floating-point type. This means that, just like arithmetic on
+``float`` or ``double``, arithmetic on ``_Float16`` operands is formally performed in the
+``_Float16`` type, so that e.g. the result of adding two ``_Float16`` values has type
+``_Float16``. The behavior of ``_Float16`` is specified by ISO/IEC TS 18661-3:2015
+("Floating-point extensions for C"). As with ``__fp16``, Clang uses the ``binary16``
+format from IEEE 754-2008 for ``_Float16``.
+
+``_Float16`` arithmetic will be performed using native half-precision support
+when available on the target (e.g. on ARMv8.2a); otherwise it will be performed
+at a higher precision (currently always ``float``) and then truncated down to
+``_Float16``. Note that C and C++ allow intermediate floating-point operands
+of an expression to be computed with greater precision than is expressible in
+their type, so Clang may avoid intermediate truncations in certain cases; this may
+lead to results that are inconsistent with native arithmetic.
+
+It is recommended that portable code use ``_Float16`` instead of ``__fp16``,
+as it has been defined by the C standards committee and has behavior that is
+more familiar to most programmers.
+
+Because ``__fp16`` operands are always immediately promoted to ``float``, the
+common real type of ``__fp16`` and ``_Float16`` for the purposes of the usual
+arithmetic conversions is ``float``.
+
+A literal can be given ``_Float16`` type using the suffix ``f16``; for example:
+```
+ 3.14f16
+ ```
+
+Because default argument promotion only applies to the standard floating-point
+types, ``_Float16`` values are not promoted to ``double`` when passed as variadic
+or untyped arguments. As a consequence, some caution must be taken when using
+certain library facilities with ``_Float16``; for example, there is no ``printf`` format
+specifier for ``_Float16``, and (unlike ``float``) it will not be implicitly promoted to
+``double`` when passed to ``printf``, so the programmer must explicitly cast it to
+``double`` before using it with an ``%f`` or similar specifier.
Messages on ``deprecated`` and ``unavailable`` Attributes
=========================================================
Modified: cfe/trunk/include/clang/Basic/TargetInfo.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/TargetInfo.h?rev=352221&r1=352220&r2=352221&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/TargetInfo.h (original)
+++ cfe/trunk/include/clang/Basic/TargetInfo.h Fri Jan 25 09:27:57 2019
@@ -63,6 +63,7 @@ protected:
bool HasLegalHalfType; // True if the backend supports operations on the half
// LLVM IR type.
bool HasFloat128;
+ bool HasFloat16;
unsigned char PointerWidth, PointerAlign;
unsigned char BoolWidth, BoolAlign;
unsigned char IntWidth, IntAlign;
@@ -516,6 +517,9 @@ public:
/// Determine whether the __float128 type is supported on this target.
virtual bool hasFloat128Type() const { return HasFloat128; }
+ /// Determine whether the _Float16 type is supported on this target.
+ virtual bool hasFloat16Type() const { return HasFloat16; }
+
/// Return the alignment that is suitable for storing any
/// object with a fundamental alignment requirement.
unsigned getSuitableAlign() const { return SuitableAlign; }
Modified: cfe/trunk/lib/Basic/TargetInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/TargetInfo.cpp?rev=352221&r1=352220&r2=352221&view=diff
==============================================================================
--- cfe/trunk/lib/Basic/TargetInfo.cpp (original)
+++ cfe/trunk/lib/Basic/TargetInfo.cpp Fri Jan 25 09:27:57 2019
@@ -34,6 +34,7 @@ TargetInfo::TargetInfo(const llvm::Tripl
NoAsmVariants = false;
HasLegalHalfType = false;
HasFloat128 = false;
+ HasFloat16 = false;
PointerWidth = PointerAlign = 32;
BoolWidth = BoolAlign = 8;
IntWidth = IntAlign = 32;
Modified: cfe/trunk/lib/Basic/Targets/AArch64.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/Targets/AArch64.cpp?rev=352221&r1=352220&r2=352221&view=diff
==============================================================================
--- cfe/trunk/lib/Basic/Targets/AArch64.cpp (original)
+++ cfe/trunk/lib/Basic/Targets/AArch64.cpp Fri Jan 25 09:27:57 2019
@@ -49,6 +49,7 @@ AArch64TargetInfo::AArch64TargetInfo(con
// All AArch64 implementations support ARMv8 FP, which makes half a legal type.
HasLegalHalfType = true;
+ HasFloat16 = true;
LongWidth = LongAlign = PointerWidth = PointerAlign = 64;
MaxVectorAlign = 128;
Modified: cfe/trunk/lib/Basic/Targets/ARM.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/Targets/ARM.cpp?rev=352221&r1=352220&r2=352221&view=diff
==============================================================================
--- cfe/trunk/lib/Basic/Targets/ARM.cpp (original)
+++ cfe/trunk/lib/Basic/Targets/ARM.cpp Fri Jan 25 09:27:57 2019
@@ -396,6 +396,7 @@ bool ARMTargetInfo::handleTargetFeatures
SoftFloat = SoftFloatABI = false;
HWDiv = 0;
DotProd = 0;
+ HasFloat16 = true;
// This does not diagnose illegal cases like having both
// "+vfpv2" and "+vfpv3" or having "+neon" and "+fp-only-sp".
Modified: cfe/trunk/lib/Basic/Targets/SPIR.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/Targets/SPIR.h?rev=352221&r1=352220&r2=352221&view=diff
==============================================================================
--- cfe/trunk/lib/Basic/Targets/SPIR.h (original)
+++ cfe/trunk/lib/Basic/Targets/SPIR.h Fri Jan 25 09:27:57 2019
@@ -47,6 +47,7 @@ public:
AddrSpaceMap = &SPIRAddrSpaceMap;
UseAddrSpaceMapMangling = true;
HasLegalHalfType = true;
+ HasFloat16 = true;
// Define available target features
// These must be defined in sorted order!
NoAsmVariants = true;
Modified: cfe/trunk/lib/Sema/SemaType.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaType.cpp?rev=352221&r1=352220&r2=352221&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaType.cpp (original)
+++ cfe/trunk/lib/Sema/SemaType.cpp Fri Jan 25 09:27:57 2019
@@ -1441,7 +1441,12 @@ static QualType ConvertDeclSpecToType(Ty
else
Result = Context.Int128Ty;
break;
- case DeclSpec::TST_float16: Result = Context.Float16Ty; break;
+ case DeclSpec::TST_float16:
+ if (!S.Context.getTargetInfo().hasFloat16Type())
+ S.Diag(DS.getTypeSpecTypeLoc(), diag::err_type_unsupported)
+ << "_Float16";
+ Result = Context.Float16Ty;
+ break;
case DeclSpec::TST_half: Result = Context.HalfTy; break;
case DeclSpec::TST_float: Result = Context.FloatTy; break;
case DeclSpec::TST_double:
Modified: cfe/trunk/test/AST/float16.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/AST/float16.cpp?rev=352221&r1=352220&r2=352221&view=diff
==============================================================================
--- cfe/trunk/test/AST/float16.cpp (original)
+++ cfe/trunk/test/AST/float16.cpp Fri Jan 25 09:27:57 2019
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -std=c++11 -ast-dump %s | FileCheck %s --strict-whitespace
-// RUN: %clang_cc1 -std=c++11 -ast-dump -fnative-half-type %s | FileCheck %s --check-prefix=CHECK-NATIVE --strict-whitespace
+// RUN: %clang_cc1 -std=c++11 -ast-dump -triple aarch64-linux-gnu %s | FileCheck %s --strict-whitespace
+// RUN: %clang_cc1 -std=c++11 -ast-dump -triple aarch64-linux-gnu -fnative-half-type %s | FileCheck %s --check-prefix=CHECK-NATIVE --strict-whitespace
/* Various contexts where type _Float16 can appear. */
Modified: cfe/trunk/test/CodeGenCXX/float16-declarations.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/float16-declarations.cpp?rev=352221&r1=352220&r2=352221&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/float16-declarations.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/float16-declarations.cpp Fri Jan 25 09:27:57 2019
@@ -1,5 +1,4 @@
// RUN: %clang -std=c++11 --target=aarch64-arm--eabi -S -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-AARCH64
-// RUN: %clang -std=c++11 --target=x86_64 -S -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-X86
/* Various contexts where type _Float16 can appear. */
@@ -15,7 +14,6 @@ namespace {
_Float16 arr1n[10];
// CHECK-AARCH64-DAG: @_ZN12_GLOBAL__N_15arr1nE = internal global [10 x half] zeroinitializer, align 2
-// CHECK-X86-DAG: @_ZN12_GLOBAL__N_15arr1nE = internal global [10 x half] zeroinitializer, align 16
_Float16 arr2n[] = { 1.2, 3.0, 3.e4 };
// CHECK-DAG: @_ZN12_GLOBAL__N_15arr2nE = internal global [3 x half] [half 0xH3CCD, half 0xH4200, half 0xH7753], align 2
@@ -30,14 +28,12 @@ namespace {
_Float16 f1f;
// CHECK-AARCH64-DAG: @f1f = dso_local global half 0xH0000, align 2
-// CHECK-X86-DAG: @f1f = dso_local global half 0xH0000, align 2
_Float16 f2f = 32.4;
// CHECK-DAG: @f2f = dso_local global half 0xH500D, align 2
_Float16 arr1f[10];
// CHECK-AARCH64-DAG: @arr1f = dso_local global [10 x half] zeroinitializer, align 2
-// CHECK-X86-DAG: @arr1f = dso_local global [10 x half] zeroinitializer, align 16
_Float16 arr2f[] = { -1.2, -3.0, -3.e4 };
// CHECK-DAG: @arr2f = dso_local global [3 x half] [half 0xHBCCD, half 0xHC200, half 0xHF753], align 2
@@ -137,8 +133,6 @@ int main(void) {
long double cvtld = f2n;
//CHECK-AARCh64-DAG: [[H2LD:%[a-z0-9]+]] = fpext half {{%[0-9]+}} to fp128
//CHECK-AARCh64-DAG: store fp128 [[H2LD]], fp128* %{{.*}}, align 16
-//CHECK-X86-DAG: [[H2LD:%[a-z0-9]+]] = fpext half {{%[0-9]+}} to x86_fp80
-//CHECK-X86-DAG: store x86_fp80 [[H2LD]], x86_fp80* %{{.*}}, align 16
_Float16 f2h = 42.0f;
//CHECK-DAG: store half 0xH5140, half* %{{.*}}, align 2
Modified: cfe/trunk/test/CodeGenCXX/mangle-ms.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/mangle-ms.cpp?rev=352221&r1=352220&r2=352221&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/mangle-ms.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/mangle-ms.cpp Fri Jan 25 09:27:57 2019
@@ -1,5 +1,6 @@
// RUN: %clang_cc1 -fblocks -emit-llvm %s -o - -triple=i386-pc-win32 -std=c++98 | FileCheck %s
// RUN: %clang_cc1 -fblocks -emit-llvm %s -o - -triple=x86_64-pc-win32 -std=c++98| FileCheck -check-prefix X64 %s
+// RUN: %clang_cc1 -fblocks -emit-llvm %s -o - -triple=aarch64-pc-win32 -std=c++98 -DARM | FileCheck -check-prefixes=X64,ARM %s
int a;
// CHECK-DAG: @"?a@@3HA"
@@ -466,10 +467,12 @@ namespace Complex {
// CHECK-DAG: define dso_local void @"?f at Complex@@YAXU?$_Complex at H@__clang@@@Z"(
void f(_Complex int) {}
}
+#ifdef ARM
namespace Float16 {
-// CHECK-DAG: define dso_local void @"?f at Float16@@YAXU_Float16 at __clang@@@Z"(
+// ARM-DAG: define dso_local void @"?f at Float16@@YAXU_Float16 at __clang@@@Z"(
void f(_Float16) {}
}
+#endif // ARM
namespace PR26029 {
template <class>
Modified: cfe/trunk/test/Lexer/half-literal.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Lexer/half-literal.cpp?rev=352221&r1=352220&r2=352221&view=diff
==============================================================================
--- cfe/trunk/test/Lexer/half-literal.cpp (original)
+++ cfe/trunk/test/Lexer/half-literal.cpp Fri Jan 25 09:27:57 2019
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -pedantic %s
+// RUN: %clang_cc1 -fsyntax-only -verify -pedantic -triple aarch64-linux-gnu %s
float a = 1.0h; // expected-error{{no matching literal operator for call to 'operator""h' with argument of type 'long double' or 'const char *', and no matching literal operator template}}
float b = 1.0H; // expected-error{{invalid suffix 'H' on floating constant}}
Added: cfe/trunk/test/Sema/Float16.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/Float16.c?rev=352221&view=auto
==============================================================================
--- cfe/trunk/test/Sema/Float16.c (added)
+++ cfe/trunk/test/Sema/Float16.c Fri Jan 25 09:27:57 2019
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-linux-pc %s
+// RUN: %clang_cc1 -fsyntax-only -verify -triple spir-unknown-unknown %s -DHAVE
+// RUN: %clang_cc1 -fsyntax-only -verify -triple armv7a-linux-gnu %s -DHAVE
+// RUN: %clang_cc1 -fsyntax-only -verify -triple aarch64-linux-gnu %s -DHAVE
+
+#ifdef HAVE
+// expected-no-diagnostics
+#else
+// expected-error at +2{{_Float16 is not supported on this target}}
+#endif // HAVE
+_Float16 f;
Propchange: cfe/trunk/test/Sema/Float16.c
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