diff --git a/ChangeLog b/ChangeLog
index cc84fdae..d5c1efca 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2017-02-25 Even Rouault <even.rouault at spatialys.com>
+
+	* libtiff/tif_fax3.c, tif_predict.c, tif_getimage.c: fix GCC 7
+	-Wimplicit-fallthrough warnings.
+
 2017-02-18 Even Rouault <even.rouault at spatialys.com>
 
 	* libtiff/tif_pixarlog.c: fix memory leak in error code path of
diff --git a/libtiff/tif_fax3.c b/libtiff/tif_fax3.c
index 16bb4d36..519b285b 100644
--- a/libtiff/tif_fax3.c
+++ b/libtiff/tif_fax3.c
@@ -1,4 +1,4 @@
-/* $Id: tif_fax3.c,v 1.78 2016-09-04 21:32:56 erouault Exp $ */
+/* $Id: tif_fax3.c,v 1.79 2017-02-25 17:05:12 erouault Exp $ */
 
 /*
  * Copyright (c) 1990-1997 Sam Leffler
@@ -329,34 +329,64 @@ Fax3Decode2D(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
 #if SIZEOF_UNSIGNED_LONG == 8
 # define FILL(n, cp)							    \
     switch (n) {							    \
-    case 15:(cp)[14] = 0xff; case 14:(cp)[13] = 0xff; case 13: (cp)[12] = 0xff;\
-    case 12:(cp)[11] = 0xff; case 11:(cp)[10] = 0xff; case 10: (cp)[9] = 0xff;\
-    case  9: (cp)[8] = 0xff; case  8: (cp)[7] = 0xff; case  7: (cp)[6] = 0xff;\
-    case  6: (cp)[5] = 0xff; case  5: (cp)[4] = 0xff; case  4: (cp)[3] = 0xff;\
-    case  3: (cp)[2] = 0xff; case  2: (cp)[1] = 0xff;			      \
-    case  1: (cp)[0] = 0xff; (cp) += (n); case 0:  ;			      \
+    case 15:(cp)[14] = 0xff; /*-fallthrough*/ \
+    case 14:(cp)[13] = 0xff; /*-fallthrough*/ \
+    case 13:(cp)[12] = 0xff; /*-fallthrough*/ \
+    case 12:(cp)[11] = 0xff; /*-fallthrough*/ \
+    case 11:(cp)[10] = 0xff; /*-fallthrough*/ \
+    case 10: (cp)[9] = 0xff; /*-fallthrough*/ \
+    case  9: (cp)[8] = 0xff; /*-fallthrough*/ \
+    case  8: (cp)[7] = 0xff; /*-fallthrough*/ \
+    case  7: (cp)[6] = 0xff; /*-fallthrough*/ \
+    case  6: (cp)[5] = 0xff; /*-fallthrough*/ \
+    case  5: (cp)[4] = 0xff; /*-fallthrough*/ \
+    case  4: (cp)[3] = 0xff; /*-fallthrough*/ \
+    case  3: (cp)[2] = 0xff; /*-fallthrough*/ \
+    case  2: (cp)[1] = 0xff; /*-fallthrough*/ \
+    case  1: (cp)[0] = 0xff; (cp) += (n); /*-fallthrough*/ \
+    case 0:  ;			      \
     }
 # define ZERO(n, cp)							\
     switch (n) {							\
-    case 15:(cp)[14] = 0; case 14:(cp)[13] = 0; case 13: (cp)[12] = 0;	\
-    case 12:(cp)[11] = 0; case 11:(cp)[10] = 0; case 10: (cp)[9] = 0;	\
-    case  9: (cp)[8] = 0; case  8: (cp)[7] = 0; case  7: (cp)[6] = 0;	\
-    case  6: (cp)[5] = 0; case  5: (cp)[4] = 0; case  4: (cp)[3] = 0;	\
-    case  3: (cp)[2] = 0; case  2: (cp)[1] = 0;				\
-    case  1: (cp)[0] = 0; (cp) += (n); case 0:  ;			\
+    case 15:(cp)[14] = 0; /*-fallthrough*/ \
+    case 14:(cp)[13] = 0; /*-fallthrough*/ \
+    case 13:(cp)[12] = 0; /*-fallthrough*/ \
+    case 12:(cp)[11] = 0; /*-fallthrough*/ \
+    case 11:(cp)[10] = 0; /*-fallthrough*/ \
+    case 10: (cp)[9] = 0; /*-fallthrough*/ \
+    case  9: (cp)[8] = 0; /*-fallthrough*/ \
+    case  8: (cp)[7] = 0; /*-fallthrough*/ \
+    case  7: (cp)[6] = 0; /*-fallthrough*/ \
+    case  6: (cp)[5] = 0; /*-fallthrough*/ \
+    case  5: (cp)[4] = 0; /*-fallthrough*/ \
+    case  4: (cp)[3] = 0; /*-fallthrough*/ \
+    case  3: (cp)[2] = 0; /*-fallthrough*/ \
+    case  2: (cp)[1] = 0; /*-fallthrough*/ \
+    case  1: (cp)[0] = 0; (cp) += (n); /*-fallthrough*/ \
+    case 0:  ;			\
     }
 #else
 # define FILL(n, cp)							    \
     switch (n) {							    \
-    case 7: (cp)[6] = 0xff; case 6: (cp)[5] = 0xff; case 5: (cp)[4] = 0xff; \
-    case 4: (cp)[3] = 0xff; case 3: (cp)[2] = 0xff; case 2: (cp)[1] = 0xff; \
-    case 1: (cp)[0] = 0xff; (cp) += (n); case 0:  ;			    \
+    case 7: (cp)[6] = 0xff; /*-fallthrough*/ \
+    case 6: (cp)[5] = 0xff; /*-fallthrough*/ \
+    case 5: (cp)[4] = 0xff; /*-fallthrough*/ \
+    case 4: (cp)[3] = 0xff; /*-fallthrough*/ \
+    case 3: (cp)[2] = 0xff; /*-fallthrough*/ \
+    case 2: (cp)[1] = 0xff; /*-fallthrough*/ \
+    case 1: (cp)[0] = 0xff; (cp) += (n);  /*-fallthrough*/ \
+    case 0:  ;			    \
     }
 # define ZERO(n, cp)							\
     switch (n) {							\
-    case 7: (cp)[6] = 0; case 6: (cp)[5] = 0; case 5: (cp)[4] = 0;	\
-    case 4: (cp)[3] = 0; case 3: (cp)[2] = 0; case 2: (cp)[1] = 0;	\
-    case 1: (cp)[0] = 0; (cp) += (n); case 0:  ;			\
+    case 7: (cp)[6] = 0; /*-fallthrough*/ \
+    case 6: (cp)[5] = 0; /*-fallthrough*/ \
+    case 5: (cp)[4] = 0; /*-fallthrough*/ \
+    case 4: (cp)[3] = 0; /*-fallthrough*/ \
+    case 3: (cp)[2] = 0; /*-fallthrough*/ \
+    case 2: (cp)[1] = 0; /*-fallthrough*/ \
+    case 1: (cp)[0] = 0; (cp) += (n); /*-fallthrough*/ \
+    case 0:  ;			\
     }
 #endif
 
diff --git a/libtiff/tif_getimage.c b/libtiff/tif_getimage.c
index 52a2402f..58d7fc43 100644
--- a/libtiff/tif_getimage.c
+++ b/libtiff/tif_getimage.c
@@ -1,4 +1,4 @@
-/* $Id: tif_getimage.c,v 1.102 2017-01-11 16:38:26 erouault Exp $ */
+/* $Id: tif_getimage.c,v 1.103 2017-02-25 17:05:12 erouault Exp $ */
 
 /*
  * Copyright (c) 1991-1997 Sam Leffler
@@ -1133,11 +1133,15 @@ gtStripSeparate(TIFFRGBAImage* img, uint32* raster, uint32 w, uint32 h)
 #define	REPEAT2(op)	op; op
 #define	CASE8(x,op)			\
     switch (x) {			\
-    case 7: op; case 6: op; case 5: op;	\
-    case 4: op; case 3: op; case 2: op;	\
+    case 7: op; /*-fallthrough*/ \
+    case 6: op; /*-fallthrough*/ \
+    case 5: op; /*-fallthrough*/ \
+    case 4: op; /*-fallthrough*/ \
+    case 3: op; /*-fallthrough*/ \
+    case 2: op; /*-fallthrough*/ \
     case 1: op;				\
     }
-#define	CASE4(x,op)	switch (x) { case 3: op; case 2: op; case 1: op; }
+#define	CASE4(x,op)	switch (x) { case 3: op; /*-fallthrough*/ case 2: op; /*-fallthrough*/ case 1: op; }
 #define	NOP
 
 #define	UNROLL8(w, op1, op2) {		\
@@ -2043,9 +2047,9 @@ DECLAREContigPutFunc(putcontig8bitYCbCr41tile)
 	    int32 Cr = pp[5];
 
             switch( (w&3) ) {
-              case 3: YCbCrtoRGB(cp [2], pp[2]);
-              case 2: YCbCrtoRGB(cp [1], pp[1]);
-              case 1: YCbCrtoRGB(cp [0], pp[0]);
+              case 3: YCbCrtoRGB(cp [2], pp[2]); /*-fallthrough*/
+              case 2: YCbCrtoRGB(cp [1], pp[1]); /*-fallthrough*/
+              case 1: YCbCrtoRGB(cp [0], pp[0]); /*-fallthrough*/
               case 0: break;
             }
 
diff --git a/libtiff/tif_predict.c b/libtiff/tif_predict.c
index a0012303..78b97073 100644
--- a/libtiff/tif_predict.c
+++ b/libtiff/tif_predict.c
@@ -1,4 +1,4 @@
-/* $Id: tif_predict.c,v 1.41 2016-11-20 22:31:22 erouault Exp $ */
+/* $Id: tif_predict.c,v 1.42 2017-02-25 17:05:12 erouault Exp $ */
 
 /*
  * Copyright (c) 1988-1997 Sam Leffler
@@ -259,11 +259,12 @@ PredictorSetupEncode(TIFF* tif)
 
 #define REPEAT4(n, op)		\
     switch (n) {		\
-    default: { tmsize_t i; for (i = n-4; i > 0; i--) { op; } } \
-    case 4:  op;		\
-    case 3:  op;		\
-    case 2:  op;		\
-    case 1:  op;		\
+    default: { \
+        tmsize_t i; for (i = n-4; i > 0; i--) { op; } }  /*-fallthrough*/  \
+    case 4:  op; /*-fallthrough*/ \
+    case 3:  op; /*-fallthrough*/ \
+    case 2:  op; /*-fallthrough*/ \
+    case 1:  op; /*-fallthrough*/ \
     case 0:  ;			\
     }