[RISCV] Define preprocessor definitions for 'V' extension.

[lenary]

LGTM!

clang/lib/Basic/Targets/RISCV.h

 protected:
   std::string ABI, CPU;
   bool HasM;
   bool HasA;
   bool HasF;
   bool HasD;
   bool HasC;
   bool HasB;
+  bool HasV;
   bool HasZfh;
 
 public:
   RISCVTargetInfo(const llvm::Triple &Triple, const TargetOptions &)
       : TargetInfo(Triple), HasM(false), HasA(false), HasF(false), HasD(false),
-        HasC(false), HasB(false), HasZfh(false) {
+        HasC(false), HasB(false), HasV(false), HasZfh(false) {
     LongDoubleWidth = 128;
     LongDoubleAlign = 128;
     LongDoubleFormat = &llvm::APFloat::IEEEquad();
     SuitableAlign = 128;
     WCharType = SignedInt;
     WIntType = UnsignedInt;
   }
 

clang/lib/Basic/Targets/RISCV.cpp

void RISCVTargetInfo::getTargetDefines(const LangOptions &Opts,
   }
 
   if (HasC)
     Builder.defineMacro("__riscv_compressed");
 
   if (HasB)
     Builder.defineMacro("__riscv_bitmanip");
 
+  if (HasV)
+    Builder.defineMacro("__riscv_vector");
+
   if (HasZfh)
     Builder.defineMacro("__riscv_zfh");
 }
 
 /// Return true if has this feature, need to sync with handleTargetFeatures.
 bool RISCVTargetInfo::hasFeature(StringRef Feature) const {
   bool Is64Bit = getTriple().getArch() == llvm::Triple::riscv64;
   return llvm::StringSwitch<bool>(Feature)
       .Case("riscv", true)
       .Case("riscv32", !Is64Bit)
       .Case("riscv64", Is64Bit)
       .Case("m", HasM)
       .Case("a", HasA)
       .Case("f", HasF)
       .Case("d", HasD)
       .Case("c", HasC)
       .Case("experimental-b", HasB)
+      .Case("experimental-v", HasV)
       .Case("experimental-zfh", HasZfh)
       .Default(false);
 }
 
 /// Perform initialization based on the user configured set of features.
 bool RISCVTargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
                                            DiagnosticsEngine &Diags) {
   for (const auto &Feature : Features) {
     if (Feature == "+m")
       HasM = true;
     else if (Feature == "+a")
       HasA = true;
     else if (Feature == "+f")
       HasF = true;
     else if (Feature == "+d")
       HasD = true;
     else if (Feature == "+c")
       HasC = true;
     else if (Feature == "+experimental-b")
       HasB = true;
+    else if (Feature == "+experimental-v")
+      HasV = true;
     else if (Feature == "+experimental-zfh")
       HasZfh = true;
   }
 
   return true;
 }
 
 bool RISCV32TargetInfo::isValidCPUName(StringRef Name) const {

clang/test/Preprocessor/riscv-target-features.c

 // RUN: %clang -target riscv32-unknown-linux-gnu -march=rv32ifd -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-DOUBLE %s
 // RUN: %clang -target riscv64-unknown-linux-gnu -march=rv64ifd -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-DOUBLE %s
 // CHECK-DOUBLE: __riscv_float_abi_double 1
 // CHECK-DOUBLE-NOT: __riscv_float_abi_soft
 // CHECK-DOUBLE-NOT: __riscv_float_abi_single
 
+// RUN: %clang -target riscv32-unknown-linux-gnu -menable-experimental-extensions \
+// RUN:   -march=rv32iv0p9 -x c -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-V-EXT %s
+// RUN: %clang -target riscv64-unknown-linux-gnu -menable-experimental-extensions \
+// RUN:   -march=rv64iv0p9 -x c -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-V-EXT %s
+// CHECK-V-EXT: __riscv_vector 1
+//
 // RUN: %clang -target riscv32-unknown-linux-gnu -menable-experimental-extensions -march=rv32izfh0p1 -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-ZFH-EXT %s
 // RUN: %clang -target riscv64-unknown-linux-gnu -menable-experimental-extensions -march=rv64izfh0p1 -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-ZFH-EXT %s
 // CHECK-ZFH-EXT: __riscv_zfh 1