diff --git a/src/cmd/5c/txt.c b/src/cmd/5c/txt.c
index a32387bc1e..4de8908905 100644
--- a/src/cmd/5c/txt.c
+++ b/src/cmd/5c/txt.c
@@ -357,7 +357,7 @@ regfree(Node *n)
 	if(n->op != OREGISTER && n->op != OINDREG)
 		goto err;
 	i = n->reg;
-	if(i < 0 || i >= sizeof(reg))
+	if(i < 0 || i >= nelem(reg))
 		goto err;
 	if(reg[i] <= 0)
 		goto err;
diff --git a/src/cmd/6c/txt.c b/src/cmd/6c/txt.c
index 12fc5b498a..dd232f085f 100644
--- a/src/cmd/6c/txt.c
+++ b/src/cmd/6c/txt.c
@@ -411,7 +411,7 @@ regfree(Node *n)
 	if(n->op != OREGISTER && n->op != OINDREG)
 		goto err;
 	i = n->reg;
-	if(i < 0 || i >= sizeof(reg))
+	if(i < 0 || i >= nelem(reg))
 		goto err;
 	if(reg[i] <= 0)
 		goto err;
diff --git a/src/cmd/6g/gsubr.c b/src/cmd/6g/gsubr.c
index 02df69ac3c..2fea7daab8 100644
--- a/src/cmd/6g/gsubr.c
+++ b/src/cmd/6g/gsubr.c
@@ -419,7 +419,7 @@ regfree(Node *n)
 	i = n->val.u.reg;
 	if(i == D_SP)
 		return;
-	if(i < 0 || i >= sizeof(reg))
+	if(i < 0 || i >= nelem(reg))
 		fatal("regfree: reg out of range");
 	if(reg[i] <= 0)
 		fatal("regfree: reg not allocated");
diff --git a/src/cmd/8c/txt.c b/src/cmd/8c/txt.c
index b2e0148a0a..65c551ef6f 100644
--- a/src/cmd/8c/txt.c
+++ b/src/cmd/8c/txt.c
@@ -372,7 +372,7 @@ regfree(Node *n)
 	if(n->op != OREGISTER && n->op != OINDREG)
 		goto err;
 	i = n->reg;
-	if(i < 0 || i >= sizeof(reg))
+	if(i < 0 || i >= nelem(reg))
 		goto err;
 	if(reg[i] <= 0)
 		goto err;
diff --git a/src/cmd/8g/gsubr.c b/src/cmd/8g/gsubr.c
index dd35c51b08..9cf3645965 100644
--- a/src/cmd/8g/gsubr.c
+++ b/src/cmd/8g/gsubr.c
@@ -893,7 +893,7 @@ regfree(Node *n)
 	i = n->val.u.reg;
 	if(i == D_SP)
 		return;
-	if(i < 0 || i >= sizeof(reg))
+	if(i < 0 || i >= nelem(reg))
 		fatal("regfree: reg out of range");
 	if(reg[i] <= 0)
 		fatal("regfree: reg not allocated");