r246755 - [ARM] Allow passing/returning of __fp16 arguments
Oliver Stannard via cfe-commits
cfe-commits at lists.llvm.org
Thu Sep 3 02:34:53 PDT 2015
Author: olista01
Date: Thu Sep 3 04:34:53 2015
New Revision: 246755
URL: http://llvm.org/viewvc/llvm-project?rev=246755&view=rev
Log:
[ARM] Allow passing/returning of __fp16 arguments
The ACLE (ARM C Language Extensions) 2.0 allows the __fp16 type to be
used as a functon argument or return type (ACLE 1.1 did not).
The current public release of the AAPCS (2.09) states that __fp16 values
should be converted to single-precision before being passed or returned,
but AAPCS 2.10 (to be released shortly) changes this, so that they are
passed in the least-significant 16 bits of either a GPR (for base AAPCS)
or a single-precision register (for AAPCS-VFP). This does not change how
arguments are passed if they get passed on the stack.
This patch brings clang up to compliance with the latest versions of
both of these specs.
We can now set the __ARM_FP16_ARGS ACLE predefine, and we have always
been able to set the __ARM_FP16_FORMAT_IEEE predefine (we do not support
the alternative format).
Added:
cfe/trunk/test/CodeGen/arm-fp16-arguments.c
Modified:
cfe/trunk/lib/Basic/Targets.cpp
cfe/trunk/lib/CodeGen/TargetInfo.cpp
cfe/trunk/lib/Driver/Tools.cpp
cfe/trunk/test/Preprocessor/arm-acle-6.5.c
cfe/trunk/test/Preprocessor/arm-target-features.c
Modified: cfe/trunk/lib/Basic/Targets.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/Targets.cpp?rev=246755&r1=246754&r2=246755&view=diff
==============================================================================
--- cfe/trunk/lib/Basic/Targets.cpp (original)
+++ cfe/trunk/lib/Basic/Targets.cpp Thu Sep 3 04:34:53 2015
@@ -4568,6 +4568,10 @@ public:
// ACLE predefines.
Builder.defineMacro("__ARM_ACLE", "200");
+ // FP16 support (we currently only support IEEE format).
+ Builder.defineMacro("__ARM_FP16_FORMAT_IEEE", "1");
+ Builder.defineMacro("__ARM_FP16_ARGS", "1");
+
// Subtarget options.
// FIXME: It's more complicated than this and we don't really support
Modified: cfe/trunk/lib/CodeGen/TargetInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/TargetInfo.cpp?rev=246755&r1=246754&r2=246755&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/TargetInfo.cpp (original)
+++ cfe/trunk/lib/CodeGen/TargetInfo.cpp Thu Sep 3 04:34:53 2015
@@ -4714,6 +4714,15 @@ ABIArgInfo ARMABIInfo::classifyArgumentT
return ABIArgInfo::getIndirect(0, /*ByVal=*/false);
}
+ // __fp16 gets passed as if it were an int or float, but with the top 16 bits
+ // unspecified.
+ if (Ty->isHalfType()) {
+ llvm::Type *ResType = IsEffectivelyAAPCS_VFP ?
+ llvm::Type::getFloatTy(getVMContext()) :
+ llvm::Type::getInt32Ty(getVMContext());
+ return ABIArgInfo::getDirect(ResType);
+ }
+
if (!isAggregateTypeForABI(Ty)) {
// Treat an enum type as its underlying type.
if (const EnumType *EnumTy = Ty->getAs<EnumType>()) {
@@ -4872,6 +4881,15 @@ ABIArgInfo ARMABIInfo::classifyReturnTyp
return ABIArgInfo::getIndirect(0);
}
+ // __fp16 gets returned as if it were an int or float, but with the top 16
+ // bits unspecified.
+ if (RetTy->isHalfType()) {
+ llvm::Type *ResType = IsEffectivelyAAPCS_VFP ?
+ llvm::Type::getFloatTy(getVMContext()) :
+ llvm::Type::getInt32Ty(getVMContext());
+ return ABIArgInfo::getDirect(ResType);
+ }
+
if (!isAggregateTypeForABI(RetTy)) {
// Treat an enum type as its underlying type.
if (const EnumType *EnumTy = RetTy->getAs<EnumType>())
Modified: cfe/trunk/lib/Driver/Tools.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=246755&r1=246754&r2=246755&view=diff
==============================================================================
--- cfe/trunk/lib/Driver/Tools.cpp (original)
+++ cfe/trunk/lib/Driver/Tools.cpp Thu Sep 3 04:34:53 2015
@@ -4293,9 +4293,19 @@ void Clang::ConstructJob(Compilation &C,
CmdArgs.push_back("-mstack-probe-size=0");
}
- if (getToolChain().getArch() == llvm::Triple::aarch64 ||
- getToolChain().getArch() == llvm::Triple::aarch64_be)
+ switch (getToolChain().getArch()) {
+ case llvm::Triple::aarch64:
+ case llvm::Triple::aarch64_be:
+ case llvm::Triple::arm:
+ case llvm::Triple::armeb:
+ case llvm::Triple::thumb:
+ case llvm::Triple::thumbeb:
CmdArgs.push_back("-fallow-half-arguments-and-returns");
+ break;
+
+ default:
+ break;
+ }
if (Arg *A = Args.getLastArg(options::OPT_mrestrict_it,
options::OPT_mno_restrict_it)) {
Added: cfe/trunk/test/CodeGen/arm-fp16-arguments.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/arm-fp16-arguments.c?rev=246755&view=auto
==============================================================================
--- cfe/trunk/test/CodeGen/arm-fp16-arguments.c (added)
+++ cfe/trunk/test/CodeGen/arm-fp16-arguments.c Thu Sep 3 04:34:53 2015
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -triple armv7a--none-eabi -target-abi aapcs -mfloat-abi soft -fallow-half-arguments-and-returns -emit-llvm -o - -O1 %s | FileCheck %s --check-prefix=CHECK --check-prefix=SOFT
+// RUN: %clang_cc1 -triple armv7a--none-eabi -target-abi aapcs -mfloat-abi hard -fallow-half-arguments-and-returns -emit-llvm -o - -O1 %s | FileCheck %s --check-prefix=CHECK --check-prefix=HARD
+
+__fp16 g;
+
+void t1(__fp16 a) { g = a; }
+// SOFT: define void @t1(i32 [[PARAM:%.*]])
+// SOFT: [[TRUNC:%.*]] = trunc i32 [[PARAM]] to i16
+// HARD: define arm_aapcs_vfpcc void @t1(float [[PARAM:%.*]])
+// HARD: [[BITCAST:%.*]] = bitcast float [[PARAM]] to i32
+// HARD: [[TRUNC:%.*]] = trunc i32 [[BITCAST]] to i16
+// CHECK: store i16 [[TRUNC]], i16* bitcast (half* @g to i16*)
+
+__fp16 t2() { return g; }
+// SOFT: define i32 @t2()
+// HARD: define arm_aapcs_vfpcc float @t2()
+// CHECK: [[LOAD:%.*]] = load i16, i16* bitcast (half* @g to i16*)
+// CHECK: [[ZEXT:%.*]] = zext i16 [[LOAD]] to i32
+// SOFT: ret i32 [[ZEXT]]
+// HARD: [[BITCAST:%.*]] = bitcast i32 [[ZEXT]] to float
+// HARD: ret float [[BITCAST]]
Modified: cfe/trunk/test/Preprocessor/arm-acle-6.5.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Preprocessor/arm-acle-6.5.c?rev=246755&r1=246754&r2=246755&view=diff
==============================================================================
--- cfe/trunk/test/Preprocessor/arm-acle-6.5.c (original)
+++ cfe/trunk/test/Preprocessor/arm-acle-6.5.c Thu Sep 3 04:34:53 2015
@@ -1,6 +1,6 @@
// RUN: %clang -target arm-eabi -x c -E -dM %s -o - | FileCheck %s -check-prefix CHECK-DEFAULT
-// CHECK-DEFAULT-NOT: __ARM_FP
+// CHECK-DEFAULT-NOT: __ARM_FP 0x
// RUN: %clang -target arm-eabi -mfpu=vfp -x c -E -dM %s -o - | FileCheck %s -check-prefix CHECK-SP-DP
// RUN: %clang -target arm-eabi -mfpu=vfp3 -x c -E -dM %s -o - | FileCheck %s -check-prefix CHECK-SP-DP
Modified: cfe/trunk/test/Preprocessor/arm-target-features.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Preprocessor/arm-target-features.c?rev=246755&r1=246754&r2=246755&view=diff
==============================================================================
--- cfe/trunk/test/Preprocessor/arm-target-features.c (original)
+++ cfe/trunk/test/Preprocessor/arm-target-features.c Thu Sep 3 04:34:53 2015
@@ -5,6 +5,8 @@
// CHECK: __ARM_FEATURE_CRC32 1
// CHECK: __ARM_FEATURE_DIRECTED_ROUNDING 1
// CHECK: __ARM_FEATURE_NUMERIC_MAXMIN 1
+// CHECK: __ARM_FP16_ARGS 1
+// CHECK: __ARM_FP16_FORMAT_IEEE 1
// RUN: %clang -target armv7a-none-linux-gnu -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-V7 %s
// CHECK-V7: __ARMEL__ 1
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