Add count_{leading,trailing}_zeros() functions to stdlib.

(Documentation is still yet to be written.)

stdlib.ispc

@@ -315,6 +315,113 @@ static inline uniform int lanemask() {
     return __movmsk(__mask);
 }
 
+///////////////////////////////////////////////////////////////////////////
+// count leading/trailing zeros
+
+static inline uniform unsigned int32
+count_leading_zeros(uniform unsigned int32 v) {
+    return __count_leading_zeros_i32(v);
+}
+
+static inline uniform unsigned int64
+count_leading_zeros(uniform unsigned int64 v) {
+    return __count_leading_zeros_i64(v);
+}
+
+static inline uniform unsigned int32
+count_trailing_zeros(uniform unsigned int32 v) {
+    return __count_trailing_zeros_i32(v);
+}
+
+static inline uniform unsigned int64
+count_trailing_zeros(uniform unsigned int64 v) {
+    return __count_trailing_zeros_i64(v);
+}
+
+static inline uniform int32
+count_leading_zeros(uniform int32 v) {
+    return __count_leading_zeros_i32(v);
+}
+
+static inline uniform int64
+count_leading_zeros(uniform int64 v) {
+    return __count_leading_zeros_i64(v);
+}
+
+static inline uniform int32
+count_trailing_zeros(uniform int32 v) {
+    return __count_trailing_zeros_i32(v);
+}
+
+static inline uniform int64
+count_trailing_zeros(uniform int64 v) {
+    return __count_trailing_zeros_i64(v);
+}
+
+static inline unsigned int32
+count_leading_zeros(unsigned int32 v) {
+    unsigned int32 r;
+    for (uniform int i = 0; i < programCount; ++i)
+        r = insert(r, i, __count_leading_zeros_i32(extract(v, i)));
+    return r;
+}
+
+static inline unsigned int64
+count_leading_zeros(unsigned int64 v) {
+    unsigned int64 r;
+    for (uniform int i = 0; i < programCount; ++i)
+        r = insert(r, i, __count_leading_zeros_i64(extract(v, i)));
+    return r;
+}
+
+static inline unsigned int32
+count_trailing_zeros(unsigned int32 v) {
+    unsigned int32 r;
+    for (uniform int i = 0; i < programCount; ++i)
+        r = insert(r, i, __count_trailing_zeros_i32(extract(v, i)));
+    return r;
+}
+
+static inline unsigned int64
+count_trailing_zeros(unsigned int64 v) {
+    unsigned int64 r;
+    for (uniform int i = 0; i < programCount; ++i)
+        r = insert(r, i, __count_trailing_zeros_i64(extract(v, i)));
+    return r;
+}
+
+static inline int32
+count_leading_zeros(int32 v) {
+    int32 r;
+    for (uniform int i = 0; i < programCount; ++i)
+        r = insert(r, i, __count_leading_zeros_i32(extract(v, i)));
+    return r;
+}
+
+static inline int64
+count_leading_zeros(int64 v) {
+    int64 r;
+    for (uniform int i = 0; i < programCount; ++i)
+        r = insert(r, i, __count_leading_zeros_i64(extract(v, i)));
+    return r;
+}
+
+static inline int32
+count_trailing_zeros(int32 v) {
+    int32 r;
+    for (uniform int i = 0; i < programCount; ++i)
+        r = insert(r, i, __count_trailing_zeros_i32(extract(v, i)));
+    return r;
+}
+
+static inline int64
+count_trailing_zeros(int64 v) {
+    int64 r;
+    for (uniform int i = 0; i < programCount; ++i)
+        r = insert(r, i, __count_trailing_zeros_i64(extract(v, i)));
+    return r;
+}
+
 ///////////////////////////////////////////////////////////////////////////
 // AOS/SOA conversion