Flush icache with __builtin___clear_cache() in tests when compiling with GCC

When compiling with GCC, use the builtin instruction cache flushing
mechanism in all tests where it is needed.

Quoting GCC docs: ''If the target does not require instruction cache
flushes, __builtin___clear_cache has no effect. Otherwise either
instructions are emitted in-line to clear the instruction cache or a
call to the __clear_cache function in libgcc is made.''.

tests/Gtest-dyn1.c

@@ -86,7 +86,9 @@ struct fdesc
 # define get_gp(fdesc)		(0)
 #endif
 
+#ifndef __GNUC__
 extern void flush_cache (void *addr, size_t len);
+#endif
 
 void
 template (int i, template_t self,
@@ -186,7 +188,7 @@ main (int argc, char *argv[] __attribute__((unused)))
 	    2*getpagesize(), PROT_READ | PROT_WRITE | PROT_EXEC);
 
 #ifdef __GNUC__
-  __clear_cache(mem, mem + MAX_FUNC_SIZE);
+  __builtin___clear_cache(mem, mem + MAX_FUNC_SIZE);
 #else
   flush_cache (mem, MAX_FUNC_SIZE);
 #endif

tests/flush-cache.S

@@ -1,3 +1,5 @@
+#ifndef __GNUC__
+
 #if defined(__ia64__)
 
 	.global flush_cache
@@ -80,3 +82,5 @@ flush_cache:
         /* We do not need executable stack.  */
         .section        .note.GNU-stack,"",@progbits
 #endif
+
+#endif

tests/ia64-test-dyn1.c

@@ -20,7 +20,9 @@ int verbose;
 # define EXTRA			0
 #endif
 
+#ifndef __GNUC__
 extern void flush_cache (void *addr, size_t len);
+#endif
 
 int
 make_executable (void *addr, size_t len)
@@ -31,7 +33,11 @@ make_executable (void *addr, size_t len)
       perror ("mprotect");
       return -1;
     }
+#ifdef __GNUC__
+  __builtin___clear_cache(addr, addr + len);
+#else
   flush_cache (addr, len);
+#endif
   return 0;
 }