1 files changed, 44 insertions, 1 deletions
diff --git a/libgo/runtime/go-memclr.c b/libgo/runtime/go-memclr.c
index b5d4975..53b8117 100644
--- a/libgo/runtime/go-memclr.c
+++ b/libgo/runtime/go-memclr.c
@@ -13,5 +13,48 @@ void memclrNoHeapPointers(void *, uintptr)
 void
 memclrNoHeapPointers (void *p1, uintptr len)
 {
-  __builtin_memset (p1, 0, len);
+
+#if !defined(__PPC64__)
+  __builtin_memset(p1, 0, len);
+#else
+  int64 rem,drem,i;
+  uint64 offset;
+  volatile uint64 *vp;
+
+  if (len == 0) {
+    return;
+  }
+  rem = len;
+
+  offset = (uint64)p1 % 8;
+  // This memset is OK since it can't contain
+  // an 8 byte aligned pointer.
+  if ((rem < 8) || (offset > 0 && offset+rem <= 16)) {
+    __builtin_memset(p1, 0, rem);
+    return;
+  }
+  // Move initial bytes to get to 8 byte boundary
+  if (offset > 0) {
+    __builtin_memset(p1, 0, 8-offset);
+    p1 = (void*)((char*)p1+8-offset);
+    rem -= 8-offset;
+  }
+
+  // If at least 8 bytes left, clear
+  drem = rem>>3;
+
+  vp = (volatile uint64*)(p1);
+  // Without the use of volatile here, the compiler
+  // might convert the loop into a memset.
+  for (i=0; i<drem; i++) {
+    *vp = 0;
+    vp++;
+    rem -= 8;
+  }
+  p1 = (void*)((char*)p1 + 8*drem);
+  // Clear any remaining
+  if (rem > 0) {
+    __builtin_memset (p1, 0, rem);
+  }
+#endif
 }