Try FALLTHROUGH macro

Author: cshung

src/coreclr/gc/vxsort/vxsort.h

@@ -13,6 +13,11 @@
 #endif
 #endif
 
+#if __has_cpp_attribute(fallthrough)
+#define FALLTHROUGH [[fallthrough]]
+#else
+#define FALLTHROUGH
+#endif
 
 #include <assert.h>
 #include <immintrin.h>
@@ -458,53 +463,53 @@ class vxsort {
 
             switch (InnerUnroll) {
                 case 12: d12 = MT::load_vec(nextPtr + InnerUnroll - 12);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case 11: d11 = MT::load_vec(nextPtr + InnerUnroll - 11);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case 10: d10 = MT::load_vec(nextPtr + InnerUnroll - 10);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  9: d09 = MT::load_vec(nextPtr + InnerUnroll -  9);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  8: d08 = MT::load_vec(nextPtr + InnerUnroll -  8);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  7: d07 = MT::load_vec(nextPtr + InnerUnroll -  7);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  6: d06 = MT::load_vec(nextPtr + InnerUnroll -  6);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  5: d05 = MT::load_vec(nextPtr + InnerUnroll -  5);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  4: d04 = MT::load_vec(nextPtr + InnerUnroll -  4);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  3: d03 = MT::load_vec(nextPtr + InnerUnroll -  3);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  2: d02 = MT::load_vec(nextPtr + InnerUnroll -  2);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  1: d01 = MT::load_vec(nextPtr + InnerUnroll -  1);
             }
 
             switch (InnerUnroll) {
                 case 12: partition_block(d12, P, writeLeft, writeRight);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case 11: partition_block(d11, P, writeLeft, writeRight);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case 10: partition_block(d10, P, writeLeft, writeRight);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  9: partition_block(d09, P, writeLeft, writeRight);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  8: partition_block(d08, P, writeLeft, writeRight);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  7: partition_block(d07, P, writeLeft, writeRight);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  6: partition_block(d06, P, writeLeft, writeRight);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  5: partition_block(d05, P, writeLeft, writeRight);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  4: partition_block(d04, P, writeLeft, writeRight);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  3: partition_block(d03, P, writeLeft, writeRight);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  2: partition_block(d02, P, writeLeft, writeRight);
-                [[clang::fallthrough]];
+                FALLTHROUGH;
                 case  1: partition_block(d01, P, writeLeft, writeRight);
               }
           }