Revert "UNREG: use __builtin___clear_cache where available"

This reverts commit 6dd1257fdd4d18e84d32e89bf0ec664b3c8f7b93.

Change fails vaildation:
  rts/sm/Storage.c:1351:20: error:
     error: ‘gcc_clear_cache’ defined but not used [-Werror=unused-function]
     STATIC_INLINE void gcc_clear_cache(void * begin, void * end)

1 files changed, 1 insertions, 21 deletions

diff --git a/rts/sm/Storage.c b/rts/sm/Storage.c
index 2e2834b4d7..4aa4b12868 100644
--- a/rts/sm/Storage.c
+++ b/rts/sm/Storage.c
@@ -1341,26 +1341,6 @@ StgWord calcTotalCompactW (void)
 #include <libkern/OSCacheControl.h>
 #endif
 
-#if defined(__GNUC__)
-/* __clear_cache is a libgcc function.
- * It existed before __builtin___clear_cache was introduced.
- * See Trac #8562.
- */
-extern void __clear_cache(char * begin, char * end);
-
-STATIC_INLINE void gcc_clear_cache(void * begin, void * end)
-{
-    /* __builtin___clear_cache is supported since GNU C 4.3.6.
-     * We pick 4.4 to simplify condition a bit.
-     */
-#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4)
-    __builtin___clear_cache(begin, end);
-#else
-    __clear_cache(begin, end);
-#endif
-}
-#endif /* __GNUC__ */
-
 /* On ARM and other platforms, we need to flush the cache after
    writing code into memory, so the processor reliably sees it. */
 void flushExec (W_ len, AdjustorExecutable exec_addr)
@@ -1376,7 +1356,7 @@ void flushExec (W_ len, AdjustorExecutable exec_addr)
   /* For all other platforms, fall back to a libgcc builtin. */
   unsigned char* begin = (unsigned char*)exec_addr;
   unsigned char* end   = begin + len;
-  gcc_clear_cache((void*)begin, (void*)end);
+  __clear_cache((void*)begin, (void*)end);
 #else
 #error Missing support to flush the instruction cache
 #endif