diff --git a/Makefile b/Makefile
index 5e887364..1dceec88 100644
--- a/Makefile
+++ b/Makefile
@@ -146,6 +146,11 @@ gcc6build: clean
 	gcc-6 -v
 	CC=gcc-6 $(MAKE) all MOREFLAGS="-Werror"
 
+.PHONY: gcc7build
+gcc7build: clean
+	gcc-7 -v
+	CC=gcc-7 $(MAKE) all MOREFLAGS="-Werror"
+
 .PHONY: clangbuild
 clangbuild: clean
 	clang -v
diff --git a/circle.yml b/circle.yml
index 218e33bf..8c2bd30d 100644
--- a/circle.yml
+++ b/circle.yml
@@ -3,7 +3,7 @@ dependencies:
     - sudo dpkg --add-architecture i386
     - sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test; sudo apt-get -y -qq update
     - sudo apt-get -y install gcc-powerpc-linux-gnu gcc-arm-linux-gnueabi libc6-dev-armel-cross gcc-aarch64-linux-gnu libc6-dev-arm64-cross
-    - sudo apt-get -y install libstdc++-6-dev clang gcc g++ gcc-5 gcc-6 zlib1g-dev liblzma-dev
+    - sudo apt-get -y install libstdc++-7-dev clang gcc g++ gcc-5 gcc-6 gcc-7 zlib1g-dev liblzma-dev
     - sudo apt-get -y install linux-libc-dev:i386 libc6-dev-i386
 
 test:
@@ -45,7 +45,7 @@ test:
         parallel: true
     - ? |
         if [[ "$CIRCLE_NODE_INDEX" == "0" ]]                                    ; then make ppc64build   && make clean; fi &&
-        if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then true              && make clean; fi #could add another test here
+        if [[ "$CIRCLE_NODE_TOTAL" < "2" ]] || [[ "$CIRCLE_NODE_INDEX" == "1" ]]; then make gcc7build    && make clean; fi #could add another test here
       :
         parallel: true
     - ? |
@@ -64,7 +64,7 @@ test:
     #- gcc -v; make -C tests test32 MOREFLAGS="-I/usr/include/x86_64-linux-gnu" && make clean
     #- make uasan               && make clean
     #- make asan32              && make clean
-    #- make -C tests test32 CC=clang MOREFLAGS="-g -fsanitize=address -I/usr/include/x86_64-linux-gnu" 
+    #- make -C tests test32 CC=clang MOREFLAGS="-g -fsanitize=address -I/usr/include/x86_64-linux-gnu"
   # Valgrind tests
     #- CFLAGS="-O1 -g" make -C zlibWrapper valgrindTest && make clean
     #- make -C tests valgrindTest && make clean
diff --git a/lib/decompress/zstd_decompress.c b/lib/decompress/zstd_decompress.c
index 92e80c1a..159b7b15 100644
--- a/lib/decompress/zstd_decompress.c
+++ b/lib/decompress/zstd_decompress.c
@@ -1731,7 +1731,7 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, c
             return 0;
         }
         dctx->expected = 0;   /* not necessary to copy more */
-
+        /* fall-through */
     case ZSTDds_decodeFrameHeader:
         assert(src != NULL);
         memcpy(dctx->headerBuffer + ZSTD_frameHeaderSize_prefix, src, dctx->expected);
@@ -2391,7 +2391,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
                     zds->outBuffSize = neededOutSize;
             }   }
             zds->streamStage = zdss_read;
-            /* pass-through */
+            /* fall-through */
 
         case zdss_read:
             DEBUGLOG(5, "stage zdss_read");
@@ -2416,8 +2416,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
             }   }
             if (ip==iend) { someMoreWork = 0; break; }   /* no more input */
             zds->streamStage = zdss_load;
-            /* pass-through */
-
+            /* fall-through */
         case zdss_load:
             {   size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds);
                 size_t const toLoad = neededInSize - zds->inPos;   /* should always be <= remaining space within inBuff */
@@ -2439,8 +2438,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
                     zds->outEnd = zds->outStart +  decodedSize;
             }   }
             zds->streamStage = zdss_flush;
-            /* pass-through */
-
+            /* fall-through */
         case zdss_flush:
             {   size_t const toFlushSize = zds->outEnd - zds->outStart;
                 size_t const flushedSize = ZSTD_limitCopy(op, oend-op, zds->outBuff + zds->outStart, toFlushSize);