[flang] add fveclib flag

[tblah]

-fveclib= allows users to choose a vectorized libm so that loops containing math functions are vectorized.

This is implemented as much as possible in the same way as in clang. The driver test in veclib.f90 is copied from the clang test.

[llvmbot]

@llvm/pr-subscribers-clang-codegen
@llvm/pr-subscribers-flang-driver
@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-driver

Author: Tom Eccles (tblah)

Changes

-fveclib= allows users to choose a vectorized libm so that loops containing math functions are vectorized.

This is implemented as much as possible in the same way as in clang. The driver test in veclib.f90 is copied from the clang test.

---

Full diff: https://github.com/llvm/llvm-project/pull/71734.diff

10 Files Affected:

• (modified) clang/include/clang/Driver/Options.td (+1-1)
• (modified) clang/lib/Driver/ToolChains/Flang.cpp (+34)
• (modified) flang/include/flang/Frontend/CodeGenOptions.def (+1)
• (modified) flang/include/flang/Frontend/CodeGenOptions.h (+11)
• (modified) flang/lib/Frontend/CompilerInvocation.cpp (+29)
• (modified) flang/lib/Frontend/FrontendActions.cpp (+50-8)
• (modified) flang/test/Driver/driver-help-hidden.f90 (+1)
• (modified) flang/test/Driver/driver-help.f90 (+2)
• (added) flang/test/Driver/fveclib-codegen.f90 (+13)
• (added) flang/test/Driver/fveclib.f90 (+30)

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 36052511203f65c..f275ec68e710769 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3118,7 +3118,7 @@ def fno_global_isel : Flag<["-"], "fno-global-isel">, Group<f_clang_Group>,
 def fno_experimental_isel : Flag<["-"], "fno-experimental-isel">, Group<f_clang_Group>,
   Alias<fno_global_isel>;
 def fveclib : Joined<["-"], "fveclib=">, Group<f_Group>,
-  Visibility<[ClangOption, CC1Option]>,
+  Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
     HelpText<"Use the given vector functions library">,
     Values<"Accelerate,libmvec,MASSV,SVML,SLEEF,Darwin_libsystem_m,ArmPL,none">,
     NormalizedValuesScope<"CodeGenOptions">,
diff --git a/clang/lib/Driver/ToolChains/Flang.cpp b/clang/lib/Driver/ToolChains/Flang.cpp
index 999039f83ddfb92..b5ebbc4ef37e1db 100644
--- a/clang/lib/Driver/ToolChains/Flang.cpp
+++ b/clang/lib/Driver/ToolChains/Flang.cpp
@@ -232,6 +232,40 @@ void Flang::addTargetOptions(const ArgList &Args,
     break;
   }
 
+  if (Arg *A = Args.getLastArg(options::OPT_fveclib)) {
+    StringRef Name = A->getValue();
+    if (Name == "SVML") {
+      if (Triple.getArch() != llvm::Triple::x86 &&
+          Triple.getArch() != llvm::Triple::x86_64)
+        D.Diag(diag::err_drv_unsupported_opt_for_target)
+            << Name << Triple.getArchName();
+    } else if (Name == "LIBMVEC-X86") {
+      if (Triple.getArch() != llvm::Triple::x86 &&
+          Triple.getArch() != llvm::Triple::x86_64)
+        D.Diag(diag::err_drv_unsupported_opt_for_target)
+            << Name << Triple.getArchName();
+    } else if (Name == "SLEEF" || Name == "ArmPL") {
+      if (Triple.getArch() != llvm::Triple::aarch64 &&
+          Triple.getArch() != llvm::Triple::aarch64_be)
+        D.Diag(diag::err_drv_unsupported_opt_for_target)
+            << Name << Triple.getArchName();
+    }
+
+    if (Triple.isOSDarwin()) {
+      // flang doesn't currently suport nostdlib, nodefaultlibs. Adding these
+      // here incase they are added someday
+      if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
+        if (A->getValue() == StringRef{"Accelerate"}) {
+          CmdArgs.push_back("-framework");
+          CmdArgs.push_back("Accelerate");
+          A->render(Args, CmdArgs);
+        }
+      }
+    } else {
+      A->render(Args, CmdArgs);
+    }
+  }
+
   // TODO: Add target specific flags, ABI, mtune option etc.
 }
 
diff --git a/flang/include/flang/Frontend/CodeGenOptions.def b/flang/include/flang/Frontend/CodeGenOptions.def
index 1e350869f1377e3..9d09ac1cbb251b1 100644
--- a/flang/include/flang/Frontend/CodeGenOptions.def
+++ b/flang/include/flang/Frontend/CodeGenOptions.def
@@ -37,6 +37,7 @@ CODEGENOPT(AliasAnalysis, 1, 0) ///< Enable alias analysis pass
 CODEGENOPT(Underscoring, 1, 1)
 ENUM_CODEGENOPT(RelocationModel, llvm::Reloc::Model, 3, llvm::Reloc::PIC_) ///< Name of the relocation model to use.
 ENUM_CODEGENOPT(DebugInfo,  llvm::codegenoptions::DebugInfoKind, 4,  llvm::codegenoptions::NoDebugInfo) ///< Level of debug info to generate
+ENUM_CODEGENOPT(VecLib, VectorLibrary, 3, VectorLibrary::NoLibrary) ///< Vector functions library to use
 
 #undef CODEGENOPT
 #undef ENUM_CODEGENOPT
diff --git a/flang/include/flang/Frontend/CodeGenOptions.h b/flang/include/flang/Frontend/CodeGenOptions.h
index b0e0c91e09ab38f..1eb2264560a02fa 100644
--- a/flang/include/flang/Frontend/CodeGenOptions.h
+++ b/flang/include/flang/Frontend/CodeGenOptions.h
@@ -81,6 +81,17 @@ class CodeGenOptions : public CodeGenOptionsBase {
     RK_WithPattern, // Remark pattern specified via '-Rgroup=regexp'.
   };
 
+  enum class VectorLibrary {
+    NoLibrary,  // Don't use any vector library.
+    Accelerate, // Use the Accelerate framework.
+    LIBMVEC,    // GLIBC vector math library.
+    MASSV,      // IBM MASS vector library.
+    SVML,       // Intel short vector math library.
+    SLEEF,      // SLEEF SIMD Library for Evaluating Elementary Functions.
+    Darwin_libsystem_m, // Use Darwin's libsystem_m vector functions.
+    ArmPL               // Arm Performance Libraries.
+  };
+
   /// Optimization remark with an optional regular expression pattern.
   struct OptRemark {
     RemarkKind Kind = RemarkKind::RK_Missing;
diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index ba2ecab3742587a..299694f72dfd864 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -153,6 +153,34 @@ static bool parseDebugArgs(Fortran::frontend::CodeGenOptions &opts,
   return true;
 }
 
+static bool parseVectorLibArg(Fortran::frontend::CodeGenOptions &opts,
+                              llvm::opt::ArgList &args,
+                              clang::DiagnosticsEngine &diags) {
+  llvm::opt::Arg *arg = args.getLastArg(clang::driver::options::OPT_fveclib);
+  if (!arg)
+    return true;
+
+  using VectorLibrary = Fortran::frontend::CodeGenOptions::VectorLibrary;
+  std::optional<VectorLibrary> val =
+      llvm::StringSwitch<std::optional<VectorLibrary>>(arg->getValue())
+          .Case("Accelerate", VectorLibrary::Accelerate)
+          .Case("LIBMVEC", VectorLibrary::LIBMVEC)
+          .Case("MASSV", VectorLibrary::MASSV)
+          .Case("SVML", VectorLibrary::SVML)
+          .Case("SLEEF", VectorLibrary::SLEEF)
+          .Case("Darwin_libsystem_m", VectorLibrary::Darwin_libsystem_m)
+          .Case("ArmPL", VectorLibrary::ArmPL)
+          .Case("NoLibrary", VectorLibrary::NoLibrary)
+          .Default(std::nullopt);
+  if (!val.has_value()) {
+    diags.Report(clang::diag::err_drv_invalid_value)
+        << arg->getAsString(args) << arg->getValue();
+    return false;
+  }
+  opts.setVecLib(val.value());
+  return true;
+}
+
 // Generate an OptRemark object containing info on if the -Rgroup
 // specified is enabled or not.
 static CodeGenOptions::OptRemark
@@ -1103,6 +1131,7 @@ bool CompilerInvocation::createFromArgs(
   parsePreprocessorArgs(res.getPreprocessorOpts(), args);
   parseCodeGenArgs(res.getCodeGenOpts(), args, diags);
   success &= parseDebugArgs(res.getCodeGenOpts(), args, diags);
+  success &= parseVectorLibArg(res.getCodeGenOpts(), args, diags);
   success &= parseSemaArgs(res, args, diags);
   success &= parseDialectArgs(res, args, diags);
   success &= parseDiagArgs(res, args, diags);
diff --git a/flang/lib/Frontend/FrontendActions.cpp b/flang/lib/Frontend/FrontendActions.cpp
index 73c00c8679c7ec6..7a25fb37a96d9b3 100644
--- a/flang/lib/Frontend/FrontendActions.cpp
+++ b/flang/lib/Frontend/FrontendActions.cpp
@@ -843,6 +843,44 @@ getOutputStream(CompilerInstance &ci, llvm::StringRef inFile,
   llvm_unreachable("Invalid action!");
 }
 
+static std::unique_ptr<llvm::TargetLibraryInfoImpl>
+createTLII(llvm::Triple &targetTriple, const CodeGenOptions &codeGenOpts) {
+  auto tlii = std::make_unique<llvm::TargetLibraryInfoImpl>(targetTriple);
+  assert(tlii && "Failed to create TargetLibraryInfo");
+
+  using VecLib = llvm::TargetLibraryInfoImpl::VectorLibrary;
+  VecLib vecLib = VecLib::NoLibrary;
+  switch (codeGenOpts.getVecLib()) {
+  case CodeGenOptions::VectorLibrary::Accelerate:
+    vecLib = VecLib::Accelerate;
+    break;
+  case CodeGenOptions::VectorLibrary::LIBMVEC:
+    vecLib = VecLib::LIBMVEC_X86;
+    break;
+  case CodeGenOptions::VectorLibrary::MASSV:
+    vecLib = VecLib::MASSV;
+    break;
+  case CodeGenOptions::VectorLibrary::SVML:
+    vecLib = VecLib::SVML;
+    break;
+  case CodeGenOptions::VectorLibrary::SLEEF:
+    vecLib = VecLib::SLEEFGNUABI;
+    break;
+  case CodeGenOptions::VectorLibrary::Darwin_libsystem_m:
+    vecLib = VecLib::DarwinLibSystemM;
+    break;
+  case CodeGenOptions::VectorLibrary::ArmPL:
+    vecLib = VecLib::ArmPL;
+    break;
+  case CodeGenOptions::VectorLibrary::NoLibrary:
+    vecLib = VecLib::NoLibrary;
+    break;
+  }
+
+  tlii->addVectorizableFunctionsFromVecLib(vecLib, targetTriple);
+  return tlii;
+}
+
 /// Generate target-specific machine-code or assembly file from the input LLVM
 /// module.
 ///
@@ -851,11 +889,10 @@ getOutputStream(CompilerInstance &ci, llvm::StringRef inFile,
 /// \param [in] act Backend act to run (assembly vs machine-code generation)
 /// \param [in] llvmModule LLVM module to lower to assembly/machine-code
 /// \param [out] os Output stream to emit the generated code to
-static void generateMachineCodeOrAssemblyImpl(clang::DiagnosticsEngine &diags,
-                                              llvm::TargetMachine &tm,
-                                              BackendActionTy act,
-                                              llvm::Module &llvmModule,
-                                              llvm::raw_pwrite_stream &os) {
+static void generateMachineCodeOrAssemblyImpl(
+    clang::DiagnosticsEngine &diags, llvm::TargetMachine &tm,
+    BackendActionTy act, llvm::Module &llvmModule, llvm::raw_pwrite_stream &os,
+    const CodeGenOptions &codeGenOpts) {
   assert(((act == BackendActionTy::Backend_EmitObj) ||
           (act == BackendActionTy::Backend_EmitAssembly)) &&
          "Unsupported action");
@@ -869,8 +906,7 @@ static void generateMachineCodeOrAssemblyImpl(clang::DiagnosticsEngine &diags,
 
   llvm::Triple triple(llvmModule.getTargetTriple());
   std::unique_ptr<llvm::TargetLibraryInfoImpl> tlii =
-      std::make_unique<llvm::TargetLibraryInfoImpl>(triple);
-  assert(tlii && "Failed to create TargetLibraryInfo");
+      createTLII(triple, codeGenOpts);
   codeGenPasses.add(new llvm::TargetLibraryInfoWrapperPass(*tlii));
 
   llvm::CodeGenFileType cgft = (act == BackendActionTy::Backend_EmitAssembly)
@@ -923,6 +959,12 @@ void CodeGenAction::runOptimizationPipeline(llvm::raw_pwrite_stream &os) {
   get##Ext##PluginInfo().RegisterPassBuilderCallbacks(pb);
 #include "llvm/Support/Extension.def"
 
+  // Register the target library analysis directly and give it a customized
+  // preset TLI depending on -fveclib
+  llvm::Triple triple(llvmModule->getTargetTriple());
+  std::unique_ptr<llvm::TargetLibraryInfoImpl> tlii = createTLII(triple, opts);
+  fam.registerPass([&] { return llvm::TargetLibraryAnalysis(*tlii); });
+
   // Register all the basic analyses with the managers.
   pb.registerModuleAnalyses(mam);
   pb.registerCGSCCAnalyses(cgam);
@@ -1228,7 +1270,7 @@ void CodeGenAction::executeAction() {
       action == BackendActionTy::Backend_EmitObj) {
     generateMachineCodeOrAssemblyImpl(
         diags, *tm, action, *llvmModule,
-        ci.isOutputStreamNull() ? *os : ci.getOutputStream());
+        ci.isOutputStreamNull() ? *os : ci.getOutputStream(), codeGenOpts);
     return;
   }
 }
diff --git a/flang/test/Driver/driver-help-hidden.f90 b/flang/test/Driver/driver-help-hidden.f90
index 6d399f1d179a022..54a2ff03462d1ab 100644
--- a/flang/test/Driver/driver-help-hidden.f90
+++ b/flang/test/Driver/driver-help-hidden.f90
@@ -98,6 +98,7 @@
 ! CHECK-NEXT: -fstack-arrays          Attempt to allocate array temporaries on the stack, no matter their size
 ! CHECK-NEXT: -fsyntax-only           Run the preprocessor, parser and semantic analysis stages
 ! CHECK-NEXT: -funderscoring          Appends one trailing underscore to external names
+! CHECK-NEXT: -fveclib=<value>        Use the given vector functions library
 ! CHECK-NEXT: -fversion-loops-for-stride
 ! CHECK-NEXT:                         Create unit-strided versions of loops
 ! CHECK-NEXT: -fxor-operator          Enable .XOR. as a synonym of .NEQV.
diff --git a/flang/test/Driver/driver-help.f90 b/flang/test/Driver/driver-help.f90
index 31c9caa32ea8292..db6347aa1c628a8 100644
--- a/flang/test/Driver/driver-help.f90
+++ b/flang/test/Driver/driver-help.f90
@@ -86,6 +86,7 @@
 ! HELP-NEXT: -fstack-arrays          Attempt to allocate array temporaries on the stack, no matter their size
 ! HELP-NEXT: -fsyntax-only           Run the preprocessor, parser and semantic analysis stages
 ! HELP-NEXT: -funderscoring          Appends one trailing underscore to external names
+! HELP-NEXT: -fveclib=<value>        Use the given vector functions library
 ! HELP-NEXT: -fversion-loops-for-stride
 ! HELP-NEXT:                         Create unit-strided versions of loops
 ! HELP-NEXT: -fxor-operator          Enable .XOR. as a synonym of .NEQV.
@@ -220,6 +221,7 @@
 ! HELP-FC1-NEXT: -fstack-arrays          Attempt to allocate array temporaries on the stack, no matter their size
 ! HELP-FC1-NEXT: -fsyntax-only           Run the preprocessor, parser and semantic analysis stages
 ! HELP-FC1-NEXT: -funderscoring          Appends one trailing underscore to external names
+! HELP-FC1-NEXT: -fveclib=<value>        Use the given vector functions library
 ! HELP-FC1-NEXT: -fversion-loops-for-stride
 ! HELP-FC1-NEXT:                         Create unit-strided versions of loops
 ! HELP-FC1-NEXT: -fxor-operator          Enable .XOR. as a synonym of .NEQV.
diff --git a/flang/test/Driver/fveclib-codegen.f90 b/flang/test/Driver/fveclib-codegen.f90
new file mode 100644
index 000000000000000..e5f362aab1b6105
--- /dev/null
+++ b/flang/test/Driver/fveclib-codegen.f90
@@ -0,0 +1,13 @@
+! test that -fveclib= is passed to the backend
+! -target aarch64 so that ArmPL is available
+! RUN: %flang -S -target aarch64-unknown-linux-gnu -mcpu=neoverse-v1 -Ofast -fveclib=ArmPL -o - %s | FileCheck %s
+
+subroutine sb(a, b)
+  real :: a(:), b(:)
+  integer :: i
+  do i=1,100
+! check that we used a vectorized call to powf()
+! CHECK: armpl_svpow_f32_x
+    a(i) = a(i) ** b(i)
+  end do
+end subroutine
diff --git a/flang/test/Driver/fveclib.f90 b/flang/test/Driver/fveclib.f90
new file mode 100644
index 000000000000000..898c65b0c850aff
--- /dev/null
+++ b/flang/test/Driver/fveclib.f90
@@ -0,0 +1,30 @@
+! RUN: %flang -### -c -fveclib=none %s 2>&1 | FileCheck -check-prefix CHECK-NOLIB %s
+! RUN: %flang -### -c -fveclib=Accelerate %s 2>&1 | FileCheck -check-prefix CHECK-ACCELERATE %s
+! RUN: %flang -### -c -fveclib=libmvec %s 2>&1 | FileCheck -check-prefix CHECK-libmvec %s
+! RUN: %flang -### -c -fveclib=MASSV %s 2>&1 | FileCheck -check-prefix CHECK-MASSV %s
+! RUN: %flang -### -c -fveclib=Darwin_libsystem_m %s 2>&1 | FileCheck -check-prefix CHECK-DARWIN_LIBSYSTEM_M %s
+! RUN: %flang -### -c --target=aarch64-none-none -fveclib=SLEEF %s 2>&1 | FileCheck -check-prefix CHECK-SLEEF %s
+! RUN: %flang -### -c --target=aarch64-none-none -fveclib=ArmPL %s 2>&1 | FileCheck -check-prefix CHECK-ARMPL %s
+! RUN: not %flang -c -fveclib=something %s 2>&1 | FileCheck -check-prefix CHECK-INVALID %s
+
+! CHECK-NOLIB: "-fveclib=none"
+! CHECK-ACCELERATE: "-fveclib=Accelerate"
+! CHECK-libmvec: "-fveclib=libmvec"
+! CHECK-MASSV: "-fveclib=MASSV"
+! CHECK-DARWIN_LIBSYSTEM_M: "-fveclib=Darwin_libsystem_m"
+! CHECK-SLEEF: "-fveclib=SLEEF"
+! CHECK-ARMPL: "-fveclib=ArmPL"
+
+! CHECK-INVALID: error: invalid value 'something' in '-fveclib=something'
+
+! RUN: not %flang --target=x86-none-none -c -fveclib=SLEEF %s 2>&1 | FileCheck -check-prefix CHECK-ERROR %s
+! RUN: not %flang --target=x86-none-none -c -fveclib=ArmPL %s 2>&1 | FileCheck -check-prefix CHECK-ERROR %s
+! RUN: not %flang --target=aarch64-none-none -c -fveclib=LIBMVEC-X86 %s 2>&1 | FileCheck -check-prefix CHECK-ERROR %s
+! RUN: not %flang --target=aarch64-none-none -c -fveclib=SVML %s 2>&1 | FileCheck -check-prefix CHECK-ERROR %s
+! CHECK-ERROR: unsupported option {{.*}} for target
+
+! RUN: %flang -fveclib=Accelerate %s -target arm64-apple-ios8.0.0 -### 2>&1 | FileCheck --check-prefix=CHECK-LINK %s
+! CHECK-LINK: "-framework" "Accelerate"
+
+! TODO: if we add support for -nostdlib or -nodefaultlibs we need to test that
+! these prevent "-framework Accelerate" being added on Darwin

[kiranchandramohan]

Can this class be moved to a file in a new directory llvm/include/llvm/Frontend/Driver and shared with Clang?

[kiranchandramohan]

Can this code be moved to llvm/lib/Frontend/Driver and shared with Clang?

[kiranchandramohan]

Nice work. LGTM.

[kiranchandramohan]

Are these clang prefixes required?

[tblah]

The file imports both the clang and llvm namespaces. So now that I have added llvm::driver, driver::Driver is ambiguous.

[kiranchandramohan]

Nit: Add the new option here. May be good to have the stream as the last option.

[github-actions]

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