diff --git a/.clang-tidy b/.clang-tidy
index cfc4d35fc9..5f1732ea4e 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -6,4 +6,5 @@ Checks: [-*,
          bugprone-incorrect-roundings,
          bugprone-macro-parentheses,
          bugprone-multi-level-implicit-pointer-conversion,
+         bugprone-inc-dec-in-conditions,
 ]
diff --git a/src/analyzer/protocol/ftp/functions.bif b/src/analyzer/protocol/ftp/functions.bif
index 4f76c95ae1..a016a776a7 100644
--- a/src/analyzer/protocol/ftp/functions.bif
+++ b/src/analyzer/protocol/ftp/functions.bif
@@ -164,9 +164,17 @@ function parse_ftp_pasv%(str: string%): ftp_port
 		line += 5;	// Skip over
 	else if ( line = strchr(s, ','); line != nullptr )
 		{ // Look for comma-separated list.
-		while ( --line >= s && isdigit(*line) )
-			;	// Back up over preceding digits.
-		++line;	// now points to first digit, or beginning of s
+		do
+			{
+			// Back up over preceding digits. We'll end on the
+			// first digit or the beginning of s.
+			--line;
+			}
+		while ( line >= s && isdigit(*line) );
+
+		// Scoot forward one to point at the first digit or at the
+		// beginning of s.
+		++line;
 		}
 
 	// Make sure we didn't step past the end of the string.
diff --git a/src/analyzer/protocol/ident/Ident.cc b/src/analyzer/protocol/ident/Ident.cc
index 378f9dafb7..1b6d11e2ba 100644
--- a/src/analyzer/protocol/ident/Ident.cc
+++ b/src/analyzer/protocol/ident/Ident.cc
@@ -142,7 +142,7 @@ void Ident_Analyzer::DeliverStream(int length, const u_char* data, bool is_orig)
 
             const char* sys_end = (comma && comma < colon) ? comma : colon;
 
-            while ( --sys_end > sys_type && isspace(*sys_end) )
+            for ( ; sys_end > sys_type && isspace(*sys_end); --sys_end )
                 ;
 
             String* sys_type_s = new String((const u_char*)sys_type, sys_end - sys_type + 1, true);