[llvm] 607fb1b - [AArch64] Always add -tune-cpu argument to -cc1 driver
David Sherwood via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 19 06:57:59 PDT 2021
Author: David Sherwood
Date: 2021-10-19T14:57:51+01:00
New Revision: 607fb1bb8c91a2f284d8c63f3066ab8cc1a66955
URL: https://github.com/llvm/llvm-project/commit/607fb1bb8c91a2f284d8c63f3066ab8cc1a66955
DIFF: https://github.com/llvm/llvm-project/commit/607fb1bb8c91a2f284d8c63f3066ab8cc1a66955.diff
LOG: [AArch64] Always add -tune-cpu argument to -cc1 driver
This patch ensures that we always tune for a given CPU on AArch64
targets when the user specifies the "-mtune=xyz" flag. In the
AArch64Subtarget if the tune flag is unset we use the CPU value
instead.
I've updated the release notes here:
llvm/docs/ReleaseNotes.rst
and added tests here:
clang/test/Driver/aarch64-mtune.c
Differential Revision: https://reviews.llvm.org/D110258
Added:
clang/test/Driver/aarch64-mtune.c
Modified:
clang/docs/ReleaseNotes.rst
clang/lib/Driver/ToolChains/Clang.cpp
llvm/docs/ReleaseNotes.rst
llvm/lib/Target/AArch64/AArch64Subtarget.cpp
llvm/lib/Target/AArch64/AArch64Subtarget.h
llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
llvm/unittests/Target/AArch64/InstSizes.cpp
llvm/unittests/Target/AArch64/MatrixRegisterAliasing.cpp
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 27ff9ddc70a34..05bd9cfea3fa5 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -192,6 +192,13 @@ Arm and AArch64 Support in Clang
- Support has been added for the following processors (command-line identifiers in parentheses):
- Arm Cortex-A510 (``cortex-a510``)
+- The -mtune flag is no longer ignored for AArch64. It is now possible to
+tune code generation for a particular CPU with -mtune without setting any
+architectural features. For example, compiling with
+"-mcpu=generic -mtune=cortex-a57" will not enable any Cortex-A57 specific
+architecture features, but will enable certain optimizations specific to
+Cortex-A57 CPUs and enable the use of a more accurate scheduling model.
+
Internal API Changes
--------------------
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 316c6026adf5c..68b6950364583 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -1833,6 +1833,21 @@ void Clang::AddAArch64TargetArgs(const ArgList &Args,
}
AddAAPCSVolatileBitfieldArgs(Args, CmdArgs);
+
+ if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_mtune_EQ)) {
+ StringRef Name = A->getValue();
+
+ std::string TuneCPU;
+ if (Name == "native")
+ TuneCPU = std::string(llvm::sys::getHostCPUName());
+ else
+ TuneCPU = std::string(Name);
+
+ if (!TuneCPU.empty()) {
+ CmdArgs.push_back("-tune-cpu");
+ CmdArgs.push_back(Args.MakeArgString(TuneCPU));
+ }
+ }
}
void Clang::AddMIPSTargetArgs(const ArgList &Args,
diff --git a/clang/test/Driver/aarch64-mtune.c b/clang/test/Driver/aarch64-mtune.c
new file mode 100644
index 0000000000000..ae41f4a9983cd
--- /dev/null
+++ b/clang/test/Driver/aarch64-mtune.c
@@ -0,0 +1,42 @@
+// Ensure we support the -mtune flag.
+
+// There shouldn't be a default -mtune.
+// RUN: %clang -target aarch64-unknown-unknown -c -### %s 2>&1 \
+// RUN: | FileCheck %s -check-prefix=NOTUNE
+// NOTUNE-NOT: "-tune-cpu" "generic"
+
+// RUN: %clang -target aarch64-unknown-unknown -c -### %s -mtune=generic 2>&1 \
+// RUN: | FileCheck %s -check-prefix=GENERIC
+// GENERIC: "-tune-cpu" "generic"
+
+// RUN: %clang -target aarch64-unknown-unknown -c -### %s -mtune=neoverse-n1 2>&1 \
+// RUN: | FileCheck %s -check-prefix=NEOVERSE-N1
+// NEOVERSE-N1: "-tune-cpu" "neoverse-n1"
+
+// RUN: %clang -target aarch64-unknown-unknown -c -### %s -mtune=thunderx2t99 2>&1 \
+// RUN: | FileCheck %s -check-prefix=THUNDERX2T99
+// THUNDERX2T99: "-tune-cpu" "thunderx2t99"
+
+// Check interaction between march and mtune.
+
+// RUN: %clang -target aarch64-unknown-unknown -c -### %s -march=armv8-a 2>&1 \
+// RUN: | FileCheck %s -check-prefix=MARCHARMV8A
+// MARCHARMV8A: "-target-cpu" "generic"
+// MARCHARMV8A-NOT: "-tune-cpu" "generic"
+
+// RUN: %clang -target aarch64-unknown-unknown -c -### %s -march=armv8-a -mtune=cortex-a75 2>&1 \
+// RUN: | FileCheck %s -check-prefix=MARCHARMV8A-A75
+// MARCHARMV8A-A75: "-target-cpu" "generic"
+// MARCHARMV8A-A75: "-tune-cpu" "cortex-a75"
+
+// Check interaction between mcpu and mtune.
+
+// RUN: %clang -target aarch64-unknown-unknown -c -### %s -mcpu=thunderx 2>&1 \
+// RUN: | FileCheck %s -check-prefix=MCPUTHUNDERX
+// MCPUTHUNDERX: "-target-cpu" "thunderx"
+// MCPUTHUNDERX-NOT: "-tune-cpu"
+
+// RUN: %clang -target aarch64-unknown-unknown -c -### %s -mcpu=cortex-a75 -mtune=cortex-a57 2>&1 \
+// RUN: | FileCheck %s -check-prefix=MCPUA75-MTUNEA57
+// MCPUA75-MTUNEA57: "-target-cpu" "cortex-a75"
+// MCPUA75-MTUNEA57: "-tune-cpu" "cortex-a57"
diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index 4bac29cb1cd1c..ec8a2e4ae882c 100644
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@@ -74,6 +74,10 @@ Changes to the AArch64 Backend
------------------------------
* Added support for the Armv9-A, Armv9.1-A and Armv9.2-A architectures.
+* The compiler now recognises the "tune-cpu" function attribute to support
+the use of the -mtune frontend flag. This allows certain scheduling features
+and optimisations to be enabled independently of the architecture. If the
+"tune-cpu" attribute is absent it tunes according to the "target-cpu".
Changes to the ARM Backend
--------------------------
diff --git a/llvm/lib/Target/AArch64/AArch64Subtarget.cpp b/llvm/lib/Target/AArch64/AArch64Subtarget.cpp
index 428b6eff85baa..30dd67e619beb 100644
--- a/llvm/lib/Target/AArch64/AArch64Subtarget.cpp
+++ b/llvm/lib/Target/AArch64/AArch64Subtarget.cpp
@@ -50,15 +50,17 @@ static cl::opt<bool>
static cl::opt<bool> UseAA("aarch64-use-aa", cl::init(true),
cl::desc("Enable the use of AA during codegen."));
-AArch64Subtarget &
-AArch64Subtarget::initializeSubtargetDependencies(StringRef FS,
- StringRef CPUString) {
+AArch64Subtarget &AArch64Subtarget::initializeSubtargetDependencies(
+ StringRef FS, StringRef CPUString, StringRef TuneCPUString) {
// Determine default and user-specified characteristics
if (CPUString.empty())
CPUString = "generic";
- ParseSubtargetFeatures(CPUString, /*TuneCPU*/ CPUString, FS);
+ if (TuneCPUString.empty())
+ TuneCPUString = CPUString;
+
+ ParseSubtargetFeatures(CPUString, TuneCPUString, FS);
initializeProperties();
return *this;
@@ -198,18 +200,20 @@ void AArch64Subtarget::initializeProperties() {
}
AArch64Subtarget::AArch64Subtarget(const Triple &TT, const std::string &CPU,
+ const std::string &TuneCPU,
const std::string &FS,
const TargetMachine &TM, bool LittleEndian,
unsigned MinSVEVectorSizeInBitsOverride,
unsigned MaxSVEVectorSizeInBitsOverride)
- : AArch64GenSubtargetInfo(TT, CPU, /*TuneCPU*/ CPU, FS),
+ : AArch64GenSubtargetInfo(TT, CPU, TuneCPU, FS),
ReserveXRegister(AArch64::GPR64commonRegClass.getNumRegs()),
CustomCallSavedXRegs(AArch64::GPR64commonRegClass.getNumRegs()),
IsLittle(LittleEndian),
MinSVEVectorSizeInBits(MinSVEVectorSizeInBitsOverride),
MaxSVEVectorSizeInBits(MaxSVEVectorSizeInBitsOverride), TargetTriple(TT),
- FrameLowering(), InstrInfo(initializeSubtargetDependencies(FS, CPU)),
- TSInfo(), TLInfo(TM, *this) {
+ FrameLowering(),
+ InstrInfo(initializeSubtargetDependencies(FS, CPU, TuneCPU)), TSInfo(),
+ TLInfo(TM, *this) {
if (AArch64::isX18ReservedByDefault(TT))
ReserveXRegister.set(18);
diff --git a/llvm/lib/Target/AArch64/AArch64Subtarget.h b/llvm/lib/Target/AArch64/AArch64Subtarget.h
index d48f52cc8d210..a7cdc1d7a125c 100644
--- a/llvm/lib/Target/AArch64/AArch64Subtarget.h
+++ b/llvm/lib/Target/AArch64/AArch64Subtarget.h
@@ -298,7 +298,8 @@ class AArch64Subtarget final : public AArch64GenSubtargetInfo {
/// passed in feature string so that we can use initializer lists for
/// subtarget initialization.
AArch64Subtarget &initializeSubtargetDependencies(StringRef FS,
- StringRef CPUString);
+ StringRef CPUString,
+ StringRef TuneCPUString);
/// Initialize properties based on the selected processor family.
void initializeProperties();
@@ -307,8 +308,8 @@ class AArch64Subtarget final : public AArch64GenSubtargetInfo {
/// This constructor initializes the data members to match that
/// of the specified triple.
AArch64Subtarget(const Triple &TT, const std::string &CPU,
- const std::string &FS, const TargetMachine &TM,
- bool LittleEndian,
+ const std::string &TuneCPU, const std::string &FS,
+ const TargetMachine &TM, bool LittleEndian,
unsigned MinSVEVectorSizeInBitsOverride = 0,
unsigned MaxSVEVectorSizeInBitsOverride = 0);
diff --git a/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp b/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
index 4e6016e5487e9..6cfbeaa2fb2f0 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
@@ -355,10 +355,13 @@ AArch64TargetMachine::~AArch64TargetMachine() = default;
const AArch64Subtarget *
AArch64TargetMachine::getSubtargetImpl(const Function &F) const {
Attribute CPUAttr = F.getFnAttribute("target-cpu");
+ Attribute TuneAttr = F.getFnAttribute("tune-cpu");
Attribute FSAttr = F.getFnAttribute("target-features");
std::string CPU =
CPUAttr.isValid() ? CPUAttr.getValueAsString().str() : TargetCPU;
+ std::string TuneCPU =
+ TuneAttr.isValid() ? TuneAttr.getValueAsString().str() : CPU;
std::string FS =
FSAttr.isValid() ? FSAttr.getValueAsString().str() : TargetFS;
@@ -399,6 +402,7 @@ AArch64TargetMachine::getSubtargetImpl(const Function &F) const {
Key += "SVEMax";
Key += std::to_string(MaxSVEVectorSize);
Key += CPU;
+ Key += TuneCPU;
Key += FS;
auto &I = SubtargetMap[Key];
@@ -407,8 +411,8 @@ AArch64TargetMachine::getSubtargetImpl(const Function &F) const {
// creation will depend on the TM and the code generation flags on the
// function that reside in TargetOptions.
resetTargetOptions(F);
- I = std::make_unique<AArch64Subtarget>(TargetTriple, CPU, FS, *this,
- isLittle, MinSVEVectorSize,
+ I = std::make_unique<AArch64Subtarget>(TargetTriple, CPU, TuneCPU, FS,
+ *this, isLittle, MinSVEVectorSize,
MaxSVEVectorSize);
}
return I.get();
diff --git a/llvm/unittests/Target/AArch64/InstSizes.cpp b/llvm/unittests/Target/AArch64/InstSizes.cpp
index 6ff985fe1876e..e8528bb2445d2 100644
--- a/llvm/unittests/Target/AArch64/InstSizes.cpp
+++ b/llvm/unittests/Target/AArch64/InstSizes.cpp
@@ -29,6 +29,7 @@ std::unique_ptr<LLVMTargetMachine> createTargetMachine() {
std::unique_ptr<AArch64InstrInfo> createInstrInfo(TargetMachine *TM) {
AArch64Subtarget ST(TM->getTargetTriple(), std::string(TM->getTargetCPU()),
+ std::string(TM->getTargetCPU()),
std::string(TM->getTargetFeatureString()), *TM,
/* isLittle */ false);
return std::make_unique<AArch64InstrInfo>(ST);
diff --git a/llvm/unittests/Target/AArch64/MatrixRegisterAliasing.cpp b/llvm/unittests/Target/AArch64/MatrixRegisterAliasing.cpp
index 323848ce44b15..d1693e9b17abd 100644
--- a/llvm/unittests/Target/AArch64/MatrixRegisterAliasing.cpp
+++ b/llvm/unittests/Target/AArch64/MatrixRegisterAliasing.cpp
@@ -26,6 +26,7 @@ std::unique_ptr<LLVMTargetMachine> createTargetMachine() {
std::unique_ptr<AArch64InstrInfo> createInstrInfo(TargetMachine *TM) {
AArch64Subtarget ST(TM->getTargetTriple(), std::string(TM->getTargetCPU()),
+ std::string(TM->getTargetCPU()),
std::string(TM->getTargetFeatureString()), *TM,
/* isLittle */ false);
return std::make_unique<AArch64InstrInfo>(ST);
More information about the llvm-commits
mailing list