[Clang,Driver] Add -fveclib=Darwin_libsystem_m support.

Support for Darwin's libsystem_m's vector functions has been added to
LLVM in 93a9a8a8d9.

This patch adds support for -fveclib=Darwin_libsystem_m to Clang.

Reviewed By: arphaman

Differential Revision: https://reviews.llvm.org/D102489

clang/include/clang/Basic/CodeGenOptions.h

@@ -59,7 +59,8 @@ public:
     Accelerate,        // Use the Accelerate framework.
     LIBMVEC,           // GLIBC vector math library.
     MASSV,             // IBM MASS vector library.
-    SVML        // Intel short vector math library.
+    SVML,              // Intel short vector math library.
+    Darwin_libsystem_m // Use Darwin's libsytem_m vector functions.
   };
 
   enum ObjCDispatchMethodKind {

clang/include/clang/Driver/Options.td

@@ -2171,9 +2171,10 @@ def fno_experimental_isel : Flag<["-"], "fno-experimental-isel">, Group<f_clang_
   Alias<fno_global_isel>;
 def fveclib : Joined<["-"], "fveclib=">, Group<f_Group>, Flags<[CC1Option]>,
     HelpText<"Use the given vector functions library">,
-    Values<"Accelerate,libmvec,MASSV,SVML,none">,
+    Values<"Accelerate,libmvec,MASSV,SVML,Darwin_libsystem_m,none">,
     NormalizedValuesScope<"CodeGenOptions">,
-    NormalizedValues<["Accelerate", "LIBMVEC", "MASSV", "SVML", "NoLibrary"]>,
+    NormalizedValues<["Accelerate", "LIBMVEC", "MASSV", "SVML",
+                      "Darwin_libsystem_m", "NoLibrary"]>,
     MarshallingInfoEnum<CodeGenOpts<"VecLib">, "NoLibrary">;
 def fno_lax_vector_conversions : Flag<["-"], "fno-lax-vector-conversions">, Group<f_Group>,
   Alias<flax_vector_conversions_EQ>, AliasArgs<["none"]>;

clang/lib/CodeGen/BackendUtil.cpp

@@ -402,6 +402,10 @@ static TargetLibraryInfoImpl *createTLII(llvm::Triple &TargetTriple,
   case CodeGenOptions::SVML:
     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::SVML);
     break;
+  case CodeGenOptions::Darwin_libsystem_m:
+    TLII->addVectorizableFunctionsFromVecLib(
+        TargetLibraryInfoImpl::DarwinLibSystemM);
+    break;
   default:
     break;
   }

clang/test/CodeGen/veclib-darwin-libsystem-m.c

@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -fveclib=Darwin_libsystem_m -triple arm64-apple-darwin %s -target-cpu apple-a7 -vectorize-loops -emit-llvm -O3 -o - | FileCheck %s
+
+// Make sure -fveclib=Darwin_libsystem_m gets passed through to LLVM as
+// expected: a call to _simd_sin_f4 should be generated.
+
+extern float sinf(float);
+
+// CHECK-LABEL: define{{.*}}@apply_sin
+// CHECK: call <4 x float> @_simd_sin_f4(
+//
+void apply_sin(float *A, float *B, float *C, unsigned N) {
+  for (unsigned i = 0; i < N; i++)
+    C[i] = sinf(A[i]) + sinf(B[i]);
+}

clang/test/Driver/autocomplete.c

@@ -76,6 +76,7 @@
 // FLTOALL-NEXT: thin
 // RUN: %clang --autocomplete=-fveclib= | FileCheck %s -check-prefix=FVECLIBALL
 // FVECLIBALL: Accelerate
+// FVECLIBALL-NEXT: Darwin_libsystem_m
 // FVECLIBALL-NEXT: libmvec
 // FVECLIBALL-NEXT: MASSV
 // FVECLIBALL-NEXT: none

clang/test/Driver/fveclib.c

@@ -2,12 +2,14 @@
 // RUN: %clang -### -c -fveclib=Accelerate %s 2>&1 | FileCheck -check-prefix CHECK-ACCELERATE %s
 // RUN: %clang -### -c -fveclib=libmvec %s 2>&1 | FileCheck -check-prefix CHECK-libmvec %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
 // RUN: not %clang -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-INVALID: error: invalid value 'something' in '-fveclib=something'