1 files changed, 11 insertions, 0 deletions
diff --git a/tests/tcctest.c b/tests/tcctest.c
index 5851fb4..7fd8171 100644
--- a/tests/tcctest.c
+++ b/tests/tcctest.c
@@ -2584,6 +2584,17 @@ unsigned long mconstraint_test(struct struct1231 *r)
     return ret + a[0];
 }
 
+#ifdef __x86_64__
+int fls64(unsigned long long x)
+{
+  int bitpos = -1;
+  asm("bsrq %1,%q0"
+      : "+r" (bitpos)
+      : "rm" (x));
+  return bitpos + 1;
+}
+#endif
+
 unsigned int set;
 
 void asm_test(void)