diff --git a/lib/compress/huf_compress.c b/lib/compress/huf_compress.c
index a6c871a5..4efffbb5 100644
--- a/lib/compress/huf_compress.c
+++ b/lib/compress/huf_compress.c
@@ -565,7 +565,8 @@ HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize,
     if (srcSize < 12) return 0;   /* no saving possible : too small input */
     op += 6;   /* jumpTable */
 
-    {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, oend-op, ip, segmentSize, CTable, bmi2) );
+    assert(op <= oend);
+    {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) );
         if (cSize==0) return 0;
         assert(cSize <= 65535);
         MEM_writeLE16(ostart, (U16)cSize);
@@ -573,7 +574,8 @@ HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize,
     }
 
     ip += segmentSize;
-    {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, oend-op, ip, segmentSize, CTable, bmi2) );
+    assert(op <= oend);
+    {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) );
         if (cSize==0) return 0;
         assert(cSize <= 65535);
         MEM_writeLE16(ostart+2, (U16)cSize);
@@ -581,7 +583,8 @@ HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize,
     }
 
     ip += segmentSize;
-    {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, oend-op, ip, segmentSize, CTable, bmi2) );
+    assert(op <= oend);
+    {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) );
         if (cSize==0) return 0;
         assert(cSize <= 65535);
         MEM_writeLE16(ostart+4, (U16)cSize);
@@ -589,12 +592,14 @@ HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize,
     }
 
     ip += segmentSize;
-    {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, oend-op, ip, iend-ip, CTable, bmi2) );
+    assert(op <= oend);
+    assert(ip <= iend);
+    {   CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, (size_t)(iend-ip), CTable, bmi2) );
         if (cSize==0) return 0;
         op += cSize;
     }
 
-    return op-ostart;
+    return (size_t)(op-ostart);
 }
 
 size_t HUF_compress4X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable)
@@ -610,14 +615,15 @@ static size_t HUF_compressCTable_internal(
                 HUF_nbStreams_e nbStreams, const HUF_CElt* CTable, const int bmi2)
 {
     size_t const cSize = (nbStreams==HUF_singleStream) ?
-                         HUF_compress1X_usingCTable_internal(op, oend - op, src, srcSize, CTable, bmi2) :
-                         HUF_compress4X_usingCTable_internal(op, oend - op, src, srcSize, CTable, bmi2);
+                         HUF_compress1X_usingCTable_internal(op, (size_t)(oend - op), src, srcSize, CTable, bmi2) :
+                         HUF_compress4X_usingCTable_internal(op, (size_t)(oend - op), src, srcSize, CTable, bmi2);
     if (HUF_isError(cSize)) { return cSize; }
     if (cSize==0) { return 0; }   /* uncompressible */
     op += cSize;
     /* check compressibility */
+    assert(op >= ostart);
     if ((size_t)(op-ostart) >= srcSize-1) { return 0; }
-    return op-ostart;
+    return (size_t)(op-ostart);
 }
 
 typedef struct {
diff --git a/lib/compress/zstd_compress_sequences.c b/lib/compress/zstd_compress_sequences.c
index 23a5f353..f9f8097c 100644
--- a/lib/compress/zstd_compress_sequences.c
+++ b/lib/compress/zstd_compress_sequences.c
@@ -111,7 +111,7 @@ size_t ZSTD_fseBitCost(
             DEBUGLOG(5, "Repeat FSE_CTable has Prob[%u] == 0", s);
             return ERROR(GENERIC);
         }
-        cost += count[s] * bitCost;
+        cost += (size_t)count[s] * bitCost;
     }
     return cost >> kAccuracyLog;
 }
@@ -129,7 +129,7 @@ size_t ZSTD_crossEntropyCost(short const* norm, unsigned accuracyLog,
     unsigned s;
     assert(accuracyLog <= 8);
     for (s = 0; s <= max; ++s) {
-        unsigned const normAcc = norm[s] != -1 ? norm[s] : 1;
+        unsigned const normAcc = (norm[s] != -1) ? (unsigned)norm[s] : 1;
         unsigned const norm256 = normAcc << shift;
         assert(norm256 > 0);
         assert(norm256 < 256);
@@ -294,7 +294,7 @@ ZSTD_encodeSequences_body(
     if (MEM_32bits()) BIT_flushBits(&blockStream);
     if (longOffsets) {
         U32 const ofBits = ofCodeTable[nbSeq-1];
-        int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN-1);
+        unsigned const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN-1);
         if (extraBits) {
             BIT_addBits(&blockStream, sequences[nbSeq-1].offset, extraBits);
             BIT_flushBits(&blockStream);
@@ -331,7 +331,7 @@ ZSTD_encodeSequences_body(
             BIT_addBits(&blockStream, sequences[n].matchLength, mlBits);
             if (MEM_32bits() || (ofBits+mlBits+llBits > 56)) BIT_flushBits(&blockStream);
             if (longOffsets) {
-                int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN-1);
+                unsigned const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN-1);
                 if (extraBits) {
                     BIT_addBits(&blockStream, sequences[n].offset, extraBits);
                     BIT_flushBits(&blockStream);                            /* (7)*/