diff --git a/grep.c b/grep.c
index 52a894c989..06eed69493 100644
--- a/grep.c
+++ b/grep.c
@@ -708,6 +708,7 @@ void compile_grep_patterns(struct grep_opt *opt)
 {
 	struct grep_pat *p;
 	struct grep_expr *header_expr = prep_header_patterns(opt);
+	int extended = 0;
 
 	for (p = opt->pattern_list; p; p = p->next) {
 		switch (p->token) {
@@ -717,14 +718,14 @@ void compile_grep_patterns(struct grep_opt *opt)
 			compile_regexp(p, opt);
 			break;
 		default:
-			opt->extended = 1;
+			extended = 1;
 			break;
 		}
 	}
 
 	if (opt->all_match || opt->no_body_match || header_expr)
-		opt->extended = 1;
-	else if (!opt->extended)
+		extended = 1;
+	else if (!extended)
 		return;
 
 	p = opt->pattern_list;
@@ -790,7 +791,7 @@ void free_grep_patterns(struct grep_opt *opt)
 		free(p);
 	}
 
-	if (!opt->extended)
+	if (!opt->pattern_expression)
 		return;
 	free_pattern_expr(opt->pattern_expression);
 }
@@ -971,8 +972,6 @@ static int match_expr_eval(struct grep_opt *opt, struct grep_expr *x,
 {
 	int h = 0;
 
-	if (!x)
-		die("Not a valid grep expression");
 	switch (x->node) {
 	case GREP_NODE_TRUE:
 		h = 1;
@@ -1052,7 +1051,7 @@ static int match_line(struct grep_opt *opt,
 	struct grep_pat *p;
 	int hit = 0;
 
-	if (opt->extended)
+	if (opt->pattern_expression)
 		return match_expr(opt, bol, eol, ctx, col, icol,
 				  collect_hits);
 
@@ -1370,7 +1369,7 @@ static int should_lookahead(struct grep_opt *opt)
 {
 	struct grep_pat *p;
 
-	if (opt->extended)
+	if (opt->pattern_expression)
 		return 0; /* punt for too complex stuff */
 	if (opt->invert)
 		return 0;
diff --git a/grep.h b/grep.h
index bdcadce61b..6075f997e6 100644
--- a/grep.h
+++ b/grep.h
@@ -151,7 +151,6 @@ struct grep_opt {
 #define GREP_BINARY_TEXT	2
 	int binary;
 	int allow_textconv;
-	int extended;
 	int use_reflog_filter;
 	int relative;
 	int pathname;
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index cc15cb4ff6..2ce2b41174 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -249,6 +249,15 @@ test_expect_success 'log --grep' '
 	test_cmp expect actual
 '
 
+for noop_opt in --invert-grep --all-match
+do
+	test_expect_success "log $noop_opt without --grep is a NOOP" '
+		git log >expect &&
+		git log $noop_opt >actual &&
+		test_cmp expect actual
+	'
+done
+
 cat > expect << EOF
 second
 initial