Index: clang/lib/CodeGen/CodeGenModule.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenModule.cpp
+++ clang/lib/CodeGen/CodeGenModule.cpp
@@ -2060,6 +2060,12 @@
           getTarget().isValidCPUName(ParsedAttr.Tune))
         TuneCPU = ParsedAttr.Tune;
     }
+
+    if (SD) {
+      // Apply the given CPU name as the 'tune-cpu' so that the optimizer can
+      // favor this processor.
+      TuneCPU = SD->getCPUName(GD.getMultiVersionIndex())->getName();
+    }
   } else {
     // Otherwise just add the existing target cpu and target features to the
     // function.
Index: clang/test/CodeGen/attr-cpuspecific-avx-abi.c
===================================================================
--- clang/test/CodeGen/attr-cpuspecific-avx-abi.c
+++ clang/test/CodeGen/attr-cpuspecific-avx-abi.c
@@ -23,4 +23,6 @@
 // CHECK: define{{.*}} @foo.V() #[[V:[0-9]+]]
 
 // CHECK: attributes #[[A]] = {{.*}}"target-features"="+avx,+crc32,+cx8,+mmx,+popcnt,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+ssse3,+x87,+xsave"
+// CHECK-SAME: "tune-cpu"="generic"
 // CHECK: attributes #[[V]] = {{.*}}"target-features"="+avx,+avx2,+bmi,+cmov,+crc32,+cx8,+f16c,+fma,+lzcnt,+mmx,+movbe,+popcnt,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+ssse3,+x87,+xsave"
+// CHECK-SAME: "tune-cpu"="core_4th_gen_avx"
Index: clang/test/CodeGen/attr-cpuspecific.c
===================================================================
--- clang/test/CodeGen/attr-cpuspecific.c
+++ clang/test/CodeGen/attr-cpuspecific.c
@@ -340,5 +340,8 @@
 void OrderDispatchUsageSpecific(void) {}
 
 // CHECK: attributes #[[S]] = {{.*}}"target-features"="+avx,+cmov,+crc32,+cx8,+f16c,+mmx,+popcnt,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+ssse3,+x87,+xsave"
+// CHECK-SAME: "tune-cpu"="ivybridge"
 // CHECK: attributes #[[K]] = {{.*}}"target-features"="+adx,+avx,+avx2,+avx512cd,+avx512er,+avx512f,+avx512pf,+bmi,+cmov,+crc32,+cx8,+f16c,+fma,+lzcnt,+mmx,+movbe,+popcnt,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+ssse3,+x87,+xsave"
+// CHECK-SAME: "tune-cpu"="knl"
 // CHECK: attributes #[[O]] = {{.*}}"target-features"="+cmov,+cx8,+mmx,+movbe,+sse,+sse2,+sse3,+ssse3,+x87"
+// CHECK-SAME: "tune-cpu"="atom"