Fix an infinite loop in the MEMSYS5 auxiliary memory allocator that occurs

for memory allocations between 1GiB and 2GiB in size.  Error introduced
by check-in [949133231f8f751a].  The problem only affects builds that
include the SQLITE_ENABLE_MEMSYS5 compile-time option.

FossilOrigin-Name: 8da0f0c38a458c57f979d59b49cf4804ef81fc2eccabde1f166bab24dd1dabea

1 files changed, 6 insertions, 2 deletions

diff --git a/src/mem5.c b/src/mem5.c
index b61b93e11..336f893c6 100644
--- a/src/mem5.c
+++ b/src/mem5.c
@@ -424,9 +424,13 @@ static int memsys5Roundup(int n){
     if( n<=mem5.szAtom ) return mem5.szAtom;
     return mem5.szAtom*2;
   }
-  if( n>0x40000000 ) return 0;
+  if( n>0x10000000 ){
+    if( n>0x40000000 ) return 0;
+    if( n>0x20000000 ) return 0x40000000;
+    return 0x2000000;
+  }
   for(iFullSz=mem5.szAtom*8; iFullSz<n; iFullSz *= 4);
-  if( (iFullSz/2)>=n ) return iFullSz/2;
+  if( (iFullSz/2)>=(i64)n ) return iFullSz/2;
   return iFullSz;
 }