From 746297314f3c198a90ceab8462a40abd9fc69f26 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Mon, 22 Jun 2020 11:41:19 +0200
Subject: Fix BITFIELD i64 type handling, see #7417.

---
 src/bitops.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/bitops.c b/src/bitops.c
index f506a881b..b37bea2bf 100644
--- a/src/bitops.c
+++ b/src/bitops.c
@@ -257,7 +257,7 @@ int64_t getSignedBitfield(unsigned char *p, uint64_t offset, uint64_t bits) {
     /* If the top significant bit is 1, propagate it to all the
      * higher bits for two's complement representation of signed
      * integers. */
-    if (value & ((uint64_t)1 << (bits-1)))
+    if (bits < 64 && (value & ((uint64_t)1 << (bits-1))))
         value |= ((uint64_t)-1) << bits;
     return value;
 }
@@ -356,7 +356,6 @@ int checkSignedBitfieldOverflow(int64_t value, int64_t incr, uint64_t bits, int
 
 handle_wrap:
     {
-        uint64_t mask = ((uint64_t)-1) << bits;
         uint64_t msb = (uint64_t)1 << (bits-1);
         uint64_t a = value, b = incr, c;
         c = a+b; /* Perform addition as unsigned so that's defined. */
@@ -364,10 +363,13 @@ handle_wrap:
         /* If the sign bit is set, propagate to all the higher order
          * bits, to cap the negative value. If it's clear, mask to
          * the positive integer limit. */
-        if (c & msb) {
-            c |= mask;
-        } else {
-            c &= ~mask;
+        if (bits < 64) {
+            uint64_t mask = ((uint64_t)-1) << bits;
+            if (c & msb) {
+                c |= mask;
+            } else {
+                c &= ~mask;
+            }
         }
         *limit = c;
     }
-- 
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