diff --git a/MdePkg/Library/BaseIoLibIntrinsic/IoLibGcc.c b/MdePkg/Library/BaseIoLibIntrinsic/IoLibGcc.c
index 055f0a947e..b3a1a20256 100644
--- a/MdePkg/Library/BaseIoLibIntrinsic/IoLibGcc.c
+++ b/MdePkg/Library/BaseIoLibIntrinsic/IoLibGcc.c
@@ -32,7 +32,6 @@
   @return The value read.
 
 **/
-__inline__
 UINT8
 EFIAPI
 IoRead8 (
@@ -60,7 +59,6 @@ IoRead8 (
   @return The value written the I/O port.
 
 **/
-__inline__
 UINT8
 EFIAPI
 IoWrite8 (
@@ -87,7 +85,6 @@ IoWrite8 (
   @return The value read.
 
 **/
-__inline__
 UINT16
 EFIAPI
 IoRead16 (
@@ -117,7 +114,6 @@ IoRead16 (
   @return The value written the I/O port.
 
 **/
-__inline__
 UINT16
 EFIAPI
 IoWrite16 (
@@ -145,7 +141,6 @@ IoWrite16 (
   @return The value read.
 
 **/
-__inline__
 UINT32
 EFIAPI
 IoRead32 (
@@ -175,7 +170,6 @@ IoRead32 (
   @return The value written the I/O port.
 
 **/
-__inline__
 UINT32
 EFIAPI
 IoWrite32 (