diff --git a/library/gcm.c b/library/gcm.c
index 02265ce89..8fa4ee779 100644
--- a/library/gcm.c
+++ b/library/gcm.c
@@ -281,7 +281,7 @@ int mbedtls_gcm_starts( mbedtls_gcm_context *ctx,
     GCM_VALIDATE_RET( ctx != NULL );
     GCM_VALIDATE_RET( iv != NULL );
 
-    /* IV is are limited to 2^64 bits, so 2^61 bytes */
+    /* IV is limited to 2^64 bits, so 2^61 bytes */
     /* IV is not allowed to be zero length */
     if( iv_len == 0 || (uint64_t) iv_len >> 61 != 0 )
         return( MBEDTLS_ERR_GCM_BAD_INPUT );
@@ -335,8 +335,8 @@ int mbedtls_gcm_starts( mbedtls_gcm_context *ctx,
 /**
  * mbedtls_gcm_context::buf contains the partial state of the computation of
  * the authentication tag.
- * mbedtls_gcm_context::::add_len and mbedtls_gcm_context::len indicate
- * differenet stages of the computation:
+ * mbedtls_gcm_context::add_len and mbedtls_gcm_context::len indicate
+ * different stages of the computation:
  *     * len == 0 && add_len == 0:      initial state
  *     * len == 0 && add_len % 16 != 0: the first `add_len % 16` bytes have
  *                                      a partial block of AD that has been
@@ -357,7 +357,7 @@ int mbedtls_gcm_update_ad( mbedtls_gcm_context *ctx,
 
     GCM_VALIDATE_RET( add_len == 0 || add != NULL );
 
-    /* IV is are limited to 2^64 bits, so 2^61 bytes */
+    /* IV is limited to 2^64 bits, so 2^61 bytes */
     if( (uint64_t) add_len >> 61 != 0 )
         return( MBEDTLS_ERR_GCM_BAD_INPUT );
 
@@ -370,7 +370,7 @@ int mbedtls_gcm_update_ad( mbedtls_gcm_context *ctx,
         if( use_len > add_len )
             use_len = add_len;
 
-        for ( i = 0; i < use_len; i++ )
+        for( i = 0; i < use_len; i++ )
             ctx->buf[i+offset] ^= p[i];
 
         if( offset + use_len == 16 )
diff --git a/tests/suites/test_suite_gcm.function b/tests/suites/test_suite_gcm.function
index 005c49884..49859dda9 100644
--- a/tests/suites/test_suite_gcm.function
+++ b/tests/suites/test_suite_gcm.function
@@ -79,7 +79,7 @@ static void check_cipher_with_empty_ad( mbedtls_gcm_context *ctx,
     TEST_EQUAL( 0, mbedtls_gcm_starts( ctx, mode,
                                        iv->x, iv->len ) );
 
-    for( n = 0; n < ad_update_count; n += 1 )
+    for( n = 0; n < ad_update_count; n++ )
     {
         TEST_EQUAL( 0, mbedtls_gcm_update_ad( ctx, NULL, 0 ) );
     }
@@ -117,7 +117,7 @@ static void check_empty_cipher_with_ad( mbedtls_gcm_context *ctx,
     TEST_EQUAL( 0, mbedtls_gcm_starts( ctx, mode, iv->x, iv->len ) );
     TEST_EQUAL( 0, mbedtls_gcm_update_ad( ctx, add->x, add->len ) );
 
-    for( n = 0; n < cipher_update_count; n += 1 )
+    for( n = 0; n < cipher_update_count; n++ )
     {
         olen = 0xdeadbeef;
         TEST_EQUAL( 0, mbedtls_gcm_update( ctx, NULL, 0, NULL, 0, &olen ) );