diff --git a/include/mimalloc/bits.h b/include/mimalloc/bits.h
index e3038d11..1d4063bb 100644
--- a/include/mimalloc/bits.h
+++ b/include/mimalloc/bits.h
@@ -209,7 +209,7 @@ static inline size_t mi_popcount(size_t x) {
     return mi_builtinz(popcount)(x);
   #else
     #define MI_HAS_FAST_POPCOUNT  0
-    return (x<=1 ? x : _mi_popcount_generic(x));
+    return _mi_popcount_generic(x);
   #endif
 }
 
diff --git a/src/libc.c b/src/libc.c
index a54eec5b..b40d1204 100644
--- a/src/libc.c
+++ b/src/libc.c
@@ -383,6 +383,8 @@ static size_t mi_popcount_generic32(uint32_t x) {
 }
 
 mi_decl_noinline size_t _mi_popcount_generic(size_t x) {
+  if (x<=1) return x;
+  if (~x==0) return MI_SIZE_BITS;
   return mi_popcount_generic32(x);
 }
 
@@ -407,6 +409,8 @@ static size_t mi_popcount_generic64(uint64_t x) {
 }
 
 mi_decl_noinline size_t _mi_popcount_generic(size_t x) {
+  if (x<=1) return x;
+  if (~x==0) return MI_SIZE_BITS;
   return mi_popcount_generic64(x);
 }
 #endif