[AArch64][VecLib] Add libmvec support for AArch64 targets (#143696)

This patch adds support for the `libmvec` vector library on AArch64
targets. Currently, all `libmvec` functions in GLIBC version 2.40 are
supported. The full list of math functions enabled can be found
[here](https://github.com/bminor/glibc/blob/96abd59bf2a11ddd4e7ccaac840ec13c0b62d3ba/sysdeps/aarch64/fpu/Versions)
(up to GLIBC 2.40).

Previously, `libmvec` was only supported on x86_64 targets. Attempts to
use it on AArch64 resulted in the following error from Clang:
`unsupported option 'libmvec' for target 'aarch64'`.

Author: marykass-arm

clang/docs/ReleaseNotes.rst

@@ -359,6 +359,8 @@ Modified Compiler Flags
 
 - The ``-fchar8_t`` flag is no longer considered in non-C++ languages modes. (#GH55373)
 
+- The ``-fveclib=libmvec`` option now supports AArch64 targets (requires GLIBC 2.40 or newer).
+
 Removed Compiler Flags
 -------------------------
 

clang/include/clang/Driver/Options.td

@@ -3479,8 +3479,9 @@ def fveclib : Joined<["-"], "fveclib=">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
     HelpText<"Use the given vector functions library">,
     HelpTextForVariants<[ClangOption, CC1Option],
-      "Use the given vector functions library. "
-      "Note: -fveclib={ArmPL,SLEEF} implies -fno-math-errno">,
+      "Use the given vector functions library.\n"
+      "  Note: -fveclib={ArmPL,SLEEF,libmvec} implies -fno-math-errno.\n"
+      "  Note: -fveclib=libmvec on AArch64 requires GLIBC 2.40 or newer.">,
     Values<"Accelerate,libmvec,MASSV,SVML,SLEEF,Darwin_libsystem_m,ArmPL,AMDLIBM,none">,
     NormalizedValuesScope<"llvm::driver::VectorLibrary">,
     NormalizedValues<["Accelerate", "LIBMVEC", "MASSV", "SVML", "SLEEF",

clang/lib/Driver/ToolChains/Clang.cpp

@@ -5702,11 +5702,18 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
           Triple.getArch() != llvm::Triple::x86_64)
         D.Diag(diag::err_drv_unsupported_opt_for_target)
             << Name << Triple.getArchName();
-    } else if (Name == "libmvec" || Name == "AMDLIBM") {
+    } else if (Name == "AMDLIBM") {
       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") {
+      if (Triple.getArch() != llvm::Triple::x86 &&
+          Triple.getArch() != llvm::Triple::x86_64 &&
+          Triple.getArch() != llvm::Triple::aarch64 &&
+          Triple.getArch() != llvm::Triple::aarch64_be)
+        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 &&

clang/test/Driver/fveclib.c

@@ -1,6 +1,7 @@
 // RUN: %clang -### -c -fveclib=none %s 2>&1 | FileCheck --check-prefix=CHECK-NOLIB %s
 // RUN: %clang -### -c -fveclib=Accelerate %s 2>&1 | FileCheck --check-prefix=CHECK-ACCELERATE %s
 // RUN: %clang -### -c --target=x86_64-unknown-linux-gnu -fveclib=libmvec %s 2>&1 | FileCheck --check-prefix=CHECK-libmvec %s
+// RUN: %clang -### -c --target=aarch64-linux-gnu -fveclib=libmvec %s 2>&1 | FileCheck --check-prefix=CHECK-LIBMVEC-AARCH64 %s
 // RUN: %clang -### -c --target=x86_64-unknown-linux-gnu -fveclib=AMDLIBM %s 2>&1 | FileCheck --check-prefix=CHECK-AMDLIBM %s
 // RUN: %clang -### -c -fveclib=MASSV %s 2>&1 | FileCheck --check-prefix=CHECK-MASSV %s
 // RUN: %clang -### -c -fveclib=Darwin_libsystem_m %s 2>&1 | FileCheck --check-prefix=CHECK-DARWIN_LIBSYSTEM_M %s
@@ -12,6 +13,7 @@
 // CHECK-NOLIB: "-fveclib=none"
 // CHECK-ACCELERATE: "-fveclib=Accelerate"
 // CHECK-libmvec: "-fveclib=libmvec"
+// CHECK-LIBMVEC-AARCH64: "-fveclib=libmvec"
 // CHECK-AMDLIBM: "-fveclib=AMDLIBM"
 // CHECK-MASSV: "-fveclib=MASSV"
 // CHECK-DARWIN_LIBSYSTEM_M: "-fveclib=Darwin_libsystem_m"
@@ -23,7 +25,6 @@
 
 // RUN: not %clang --target=x86 -c -fveclib=SLEEF %s 2>&1 | FileCheck --check-prefix=CHECK-ERROR %s
 // RUN: not %clang --target=x86 -c -fveclib=ArmPL %s 2>&1 | FileCheck --check-prefix=CHECK-ERROR %s
-// RUN: not %clang --target=aarch64 -c -fveclib=libmvec %s 2>&1 | FileCheck --check-prefix=CHECK-ERROR %s
 // RUN: not %clang --target=aarch64 -c -fveclib=SVML %s 2>&1 | FileCheck --check-prefix=CHECK-ERROR %s
 // RUN: not %clang --target=aarch64 -c -fveclib=AMDLIBM %s 2>&1 | FileCheck --check-prefix=CHECK-ERROR %s
 // CHECK-ERROR: unsupported option {{.*}} for target
@@ -43,6 +44,9 @@
 // RUN: %clang -### --target=x86_64-unknown-linux-gnu -fveclib=libmvec -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-LIBMVEC %s
 // CHECK-LTO-LIBMVEC: "-plugin-opt=-vector-library=LIBMVEC"
 
+// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=libmvec -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-LIBMVEC-AARCH64 %s
+// CHECK-LTO-LIBMVEC-AARCH64: "-plugin-opt=-vector-library=LIBMVEC"
+
 // RUN: %clang -### --target=x86_64-unknown-linux-gnu -fveclib=AMDLIBM -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-AMDLIBM %s
 // CHECK-LTO-AMDLIBM: "-plugin-opt=-vector-library=AMDLIBM"
 
@@ -68,6 +72,10 @@
 // CHECK-ERRNO-LIBMVEC: "-fveclib=libmvec"
 // CHECK-ERRNO-LIBMVEC-SAME: "-fmath-errno"
 
+// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=libmvec %s 2>&1 | FileCheck --check-prefix=CHECK-ERRNO-LIBMVEC-AARCH64 %s
+// CHECK-ERRNO-LIBMVEC-AARCH64: "-fveclib=libmvec"
+// CHECK-ERRNO-LIBMVEC-AARCH64-SAME: "-fmath-errno"
+
 // RUN: %clang -### --target=x86_64-unknown-linux-gnu -fveclib=AMDLIBM %s 2>&1 | FileCheck --check-prefix=CHECK-ERRNO-AMDLIBM %s
 // CHECK-ERRNO-AMDLIBM: "-fveclib=AMDLIBM"
 // CHECK-ERRNO-AMDLIBM-SAME: "-fmath-errno"