[SPARC] Consume tune-cpu directive in the backend

[koachan]

This lets the backend read the tune-cpu directive that is emitted
by the frontend.

No changes are needed for clang as it is already emits it.

[llvmbot]

@llvm/pr-subscribers-backend-sparc

@llvm/pr-subscribers-clang

Author: Koakuma (koachan)

Changes

This lets the backend read the tune-cpu directive that is emitted
by the frontend.

No changes are needed for clang as it is already emits it.

---

Full diff: https://github.com/llvm/llvm-project/pull/77195.diff

4 Files Affected:

• (modified) clang/include/clang/Driver/Options.td (+1-1)
• (modified) llvm/lib/Target/Sparc/SparcSubtarget.cpp (+10-5)
• (modified) llvm/lib/Target/Sparc/SparcSubtarget.h (+5-2)
• (modified) llvm/lib/Target/Sparc/SparcTargetMachine.cpp (+5-2)

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index df12ba8fbcb296..070373b6b88c96 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -5119,7 +5119,7 @@ def module_file_info : Flag<["-"], "module-file-info">, Flags<[]>,
   HelpText<"Provide information about a particular module file">;
 def mthumb : Flag<["-"], "mthumb">, Group<m_Group>;
 def mtune_EQ : Joined<["-"], "mtune=">, Group<m_Group>,
-  HelpText<"Only supported on AArch64, PowerPC, RISC-V, SystemZ, and X86">;
+  HelpText<"Only supported on AArch64, PowerPC, RISC-V, SPARC, SystemZ, and X86">;
 def multi__module : Flag<["-"], "multi_module">;
 def multiply__defined__unused : Separate<["-"], "multiply_defined_unused">;
 def multiply__defined : Separate<["-"], "multiply_defined">;
diff --git a/llvm/lib/Target/Sparc/SparcSubtarget.cpp b/llvm/lib/Target/Sparc/SparcSubtarget.cpp
index 81c2137ea730f8..a5d196c502cd23 100644
--- a/llvm/lib/Target/Sparc/SparcSubtarget.cpp
+++ b/llvm/lib/Target/Sparc/SparcSubtarget.cpp
@@ -25,15 +25,18 @@ using namespace llvm;
 
 void SparcSubtarget::anchor() { }
 
-SparcSubtarget &SparcSubtarget::initializeSubtargetDependencies(StringRef CPU,
-                                                                StringRef FS) {
+SparcSubtarget &SparcSubtarget::initializeSubtargetDependencies(
+    StringRef CPU, StringRef TuneCPU, StringRef FS) {
   // Determine default and user specified characteristics
   std::string CPUName = std::string(CPU);
   if (CPUName.empty())
     CPUName = (Is64Bit) ? "v9" : "v8";
 
+  if (TuneCPU.empty())
+    TuneCPU = CPUName;
+
   // Parse features string.
-  ParseSubtargetFeatures(CPUName, /*TuneCPU*/ CPUName, FS);
+  ParseSubtargetFeatures(CPUName, TuneCPU, FS);
 
   // Popc is a v9-only instruction.
   if (!IsV9)
@@ -43,10 +46,12 @@ SparcSubtarget &SparcSubtarget::initializeSubtargetDependencies(StringRef CPU,
 }
 
 SparcSubtarget::SparcSubtarget(const Triple &TT, const std::string &CPU,
+                               const std::string &TuneCPU,
                                const std::string &FS, const TargetMachine &TM,
                                bool is64Bit)
-    : SparcGenSubtargetInfo(TT, CPU, /*TuneCPU*/ CPU, FS), TargetTriple(TT),
-      Is64Bit(is64Bit), InstrInfo(initializeSubtargetDependencies(CPU, FS)),
+    : SparcGenSubtargetInfo(TT, CPU, TuneCPU, FS), TargetTriple(TT),
+      Is64Bit(is64Bit),
+      InstrInfo(initializeSubtargetDependencies(CPU, TuneCPU, FS)),
       TLInfo(TM, *this), FrameLowering(*this) {}
 
 int SparcSubtarget::getAdjustedFrameSize(int frameSize) const {
diff --git a/llvm/lib/Target/Sparc/SparcSubtarget.h b/llvm/lib/Target/Sparc/SparcSubtarget.h
index 8e3d05d5d7e5df..4363942c0d6248 100644
--- a/llvm/lib/Target/Sparc/SparcSubtarget.h
+++ b/llvm/lib/Target/Sparc/SparcSubtarget.h
@@ -45,7 +45,8 @@ class SparcSubtarget : public SparcGenSubtargetInfo {
 
 public:
   SparcSubtarget(const Triple &TT, const std::string &CPU,
-                 const std::string &FS, const TargetMachine &TM, bool is64bit);
+                 const std::string &TuneCPU, const std::string &FS,
+                 const TargetMachine &TM, bool is64bit);
 
   const SparcInstrInfo *getInstrInfo() const override { return &InstrInfo; }
   const TargetFrameLowering *getFrameLowering() const override {
@@ -70,7 +71,9 @@ class SparcSubtarget : public SparcGenSubtargetInfo {
   /// ParseSubtargetFeatures - Parses features string setting specified
   /// subtarget options.  Definition of function is auto generated by tblgen.
   void ParseSubtargetFeatures(StringRef CPU, StringRef TuneCPU, StringRef FS);
-  SparcSubtarget &initializeSubtargetDependencies(StringRef CPU, StringRef FS);
+  SparcSubtarget &initializeSubtargetDependencies(StringRef CPU,
+                                                  StringRef TuneCPU,
+                                                  StringRef FS);
 
   bool is64Bit() const { return Is64Bit; }
 
diff --git a/llvm/lib/Target/Sparc/SparcTargetMachine.cpp b/llvm/lib/Target/Sparc/SparcTargetMachine.cpp
index dbc26636e39f1f..ae7bbcecc6c7ba 100644
--- a/llvm/lib/Target/Sparc/SparcTargetMachine.cpp
+++ b/llvm/lib/Target/Sparc/SparcTargetMachine.cpp
@@ -116,10 +116,13 @@ SparcTargetMachine::~SparcTargetMachine() = default;
 const SparcSubtarget *
 SparcTargetMachine::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;
 
@@ -137,8 +140,8 @@ SparcTargetMachine::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<SparcSubtarget>(TargetTriple, CPU, FS, *this,
-                                          this->is64Bit);
+    I = std::make_unique<SparcSubtarget>(TargetTriple, CPU, TuneCPU, FS, *this,
+                                         this->is64Bit);
   }
   return I.get();
 }