diff --git a/interface/zgemv.c b/interface/zgemv.c
index a335f6832..abf2aa710 100644
--- a/interface/zgemv.c
+++ b/interface/zgemv.c
@@ -239,6 +239,12 @@ void CNAME(enum CBLAS_ORDER order,
   buffer_size = (buffer_size + 3) & ~3;
   STACK_ALLOC(buffer_size, FLOAT, buffer);
 
+#ifdef ARCH_X86_64
+  // cgemv_t.S return NaN if there are NaN or Inf in the buffer (see bug #746)
+  if(trans && stack_alloc_size)
+    memset(buffer, 0, MIN(BUFFER_SIZE, sizeof(FLOAT) * buffer_size));
+#endif
+
 #ifdef SMP
 
   if ( 1L * m * n < 1024L * GEMM_MULTITHREAD_THRESHOLD )