diff --git a/riscv64-gen.c b/riscv64-gen.c
index beb0a46c..baf7f5ee 100644
--- a/riscv64-gen.c
+++ b/riscv64-gen.c
@@ -999,7 +999,7 @@ static void gen_opil(int op, int ll)
                     ++fc;
                 case TOK_LT:  func3 = 2; goto do_cop; // slti d, a, fc
                 case TOK_ULE:
-                    if (fc >= (1 << 11) - 1)
+                    if (fc >= (1 << 11) - 1 || fc == -1)
                       break;
                     ++fc;
                 case TOK_ULT: func3 = 3; goto do_cop; // sltiu d, a, fc
diff --git a/tests/tcctest.c b/tests/tcctest.c
index 921b0eba..027a8856 100644
--- a/tests/tcctest.c
+++ b/tests/tcctest.c
@@ -463,6 +463,15 @@ void if2t(void)
     printf("if2t:ok3\n");
 }
 
+void if3t(void)
+{
+    volatile long long i = 1;
+    if (i <= 18446744073709551615ULL)
+      ;
+    else
+      printf ("if3t:wrong 1\n");
+}
+
 void if_test(void)
 {
     if1t(1, 0, 0, 0);
@@ -470,6 +479,7 @@ void if_test(void)
     if1t(3, 2, 0, 0);
     if1t(4, 2, 3, 0);
     if2t();
+    if3t();
 }
 
 void loop_test()