diff --git a/xbyak/xbyak.h b/xbyak/xbyak.h
index 10ef35a..56f8155 100644
--- a/xbyak/xbyak.h
+++ b/xbyak/xbyak.h
@@ -644,12 +644,12 @@
 	void setBit(int bit);
 	void setOpmaskIdx(int idx, bool /*ignore_idx0*/ = true)
 	{
-		if (mask_) XBYAK_THROW(ERR_OPMASK_IS_ALREADY_SET)
+		if (mask_ && (mask_ != idx)) XBYAK_THROW(ERR_OPMASK_IS_ALREADY_SET)
 		mask_ = idx;
 	}
 	void setRounding(int idx)
 	{
-		if (rounding_) XBYAK_THROW(ERR_ROUNDING_IS_ALREADY_SET)
+		if (rounding_ && (rounding_ != idx)) XBYAK_THROW(ERR_ROUNDING_IS_ALREADY_SET)
 		rounding_ = idx;
 	}
 	void setZero() { zero_ = true; }