Fix missing clobber in blas_quickdivide assembly

common_x86_64.h

@@ -210,7 +210,7 @@ static __inline int blas_quickdivide(unsigned int x, unsigned int y){
 	
   y = blas_quick_divide_table[y];
 
-  __asm__ __volatile__  ("mull %0" :"=d" (result) :"a"(x), "0" (y));
+  __asm__ __volatile__  ("mull %0" :"=d" (result) :"+a"(x), "0" (y));
 
   return result;
 }