diff --git a/interface/zgemv.c b/interface/zgemv.c
index 6d5c720c53..05b994b2b0 100644
--- a/interface/zgemv.c
+++ b/interface/zgemv.c
@@ -244,7 +244,9 @@ void CNAME(enum CBLAS_ORDER order,
   // for alignment
   buffer_size = (buffer_size + 3) & ~3;
   STACK_ALLOC(buffer_size, FLOAT, buffer);
-
+  if(trans != CblasNoTrans)
+    // cgemv_t.S return NaN if there are NaN or Inf in the buffer (see bug #746)
+    memset(buffer, 0, sizeof(FLOAT) * buffer_size);
 #ifdef SMP
 
   nthreads_max = num_cpu_avail(2);