From 575541e32c45e04fa7c7218dd58bbb3f725f57fa Mon Sep 17 00:00:00 2001
From: "Richard C. Gobeille" <richard@voidpoint.com>
Date: Wed, 10 Jun 2020 10:37:04 -0700
Subject: [PATCH] engine: update libdivide

---
 source/thirdparty/include/libdivide.h | 51 +++++++++++++++------------
 1 file changed, 29 insertions(+), 22 deletions(-)

diff --git a/source/thirdparty/include/libdivide.h b/source/thirdparty/include/libdivide.h
index a2a1008b7..204ce6556 100644
--- a/source/thirdparty/include/libdivide.h
+++ b/source/thirdparty/include/libdivide.h
@@ -11,8 +11,8 @@
 #ifndef LIBDIVIDE_H
 #define LIBDIVIDE_H
 
-#define LIBDIVIDE_VERSION "2.0"
-#define LIBDIVIDE_VERSION_MAJOR 2
+#define LIBDIVIDE_VERSION "3.0"
+#define LIBDIVIDE_VERSION_MAJOR 3
 #define LIBDIVIDE_VERSION_MINOR 0
 
 #include <stdint.h>
@@ -20,6 +20,7 @@
 #if defined(__cplusplus)
     #include <cstdlib>
     #include <cstdio>
+    #include <type_traits>
 #else
     #include <stdlib.h>
     #include <stdio.h>
@@ -297,10 +298,17 @@ static inline int32_t libdivide_count_leading_zeros32(uint32_t val) {
     }
     return 0;
 #else
-    int32_t result = 0;
-    uint32_t hi = 1U << 31;
-    for (; ~val & hi; hi >>= 1) {
-        result++;
+    if (val == 0)
+        return 32;
+    int32_t result = 8;
+    uint32_t hi = 0xFFU << 24;
+    while ((val & hi) == 0) {
+        hi >>= 8;
+        result += 8;
+    }
+    while (val & hi) {
+        result -= 1;
+        hi <<= 1;
     }
     return result;
 #endif
@@ -1981,16 +1989,16 @@ enum {
 
 // The dispatcher selects a specific division algorithm for a given
 // type and ALGO using partial template specialization.
-template<typename T, int ALGO> struct dispatcher { };
+template<bool IS_INTEGRAL, bool IS_SIGNED, int SIZEOF, int ALGO> struct dispatcher { };
 
-template<> struct dispatcher<int32_t, BRANCHFULL> { DISPATCHER_GEN(int32_t, s32) };
-template<> struct dispatcher<int32_t, BRANCHFREE> { DISPATCHER_GEN(int32_t, s32_branchfree) };
-template<> struct dispatcher<uint32_t, BRANCHFULL> { DISPATCHER_GEN(uint32_t, u32) };
-template<> struct dispatcher<uint32_t, BRANCHFREE> { DISPATCHER_GEN(uint32_t, u32_branchfree) };
-template<> struct dispatcher<int64_t, BRANCHFULL> { DISPATCHER_GEN(int64_t, s64) };
-template<> struct dispatcher<int64_t, BRANCHFREE> { DISPATCHER_GEN(int64_t, s64_branchfree) };
-template<> struct dispatcher<uint64_t, BRANCHFULL> { DISPATCHER_GEN(uint64_t, u64) };
-template<> struct dispatcher<uint64_t, BRANCHFREE> { DISPATCHER_GEN(uint64_t, u64_branchfree) };
+template<> struct dispatcher<true, true, sizeof(int32_t), BRANCHFULL> { DISPATCHER_GEN(int32_t, s32) };
+template<> struct dispatcher<true, true, sizeof(int32_t), BRANCHFREE> { DISPATCHER_GEN(int32_t, s32_branchfree) };
+template<> struct dispatcher<true, false, sizeof(uint32_t), BRANCHFULL> { DISPATCHER_GEN(uint32_t, u32) };
+template<> struct dispatcher<true, false, sizeof(uint32_t), BRANCHFREE> { DISPATCHER_GEN(uint32_t, u32_branchfree) };
+template<> struct dispatcher<true, true, sizeof(int64_t), BRANCHFULL> { DISPATCHER_GEN(int64_t, s64) };
+template<> struct dispatcher<true, true, sizeof(int64_t), BRANCHFREE> { DISPATCHER_GEN(int64_t, s64_branchfree) };
+template<> struct dispatcher<true, false, sizeof(uint64_t), BRANCHFULL> { DISPATCHER_GEN(uint64_t, u64) };
+template<> struct dispatcher<true, false, sizeof(uint64_t), BRANCHFREE> { DISPATCHER_GEN(uint64_t, u64_branchfree) };
 
 // This is the main divider class for use by the user (C++ API).
 // The actual division algorithm is selected using the dispatcher struct
@@ -2034,9 +2042,11 @@ public:
         return div.divide(n);
     }
 #endif
+
 private:
     // Storage for the actual divisor
-    dispatcher<T, ALGO> div;
+    dispatcher<std::is_integral<T>::value, 
+               std::is_signed<T>::value, sizeof(T), ALGO> div;
 };
 
 // Overload of operator / for scalar division
@@ -2066,12 +2076,9 @@ T& operator/=(T& n, const divider<T, ALGO>& div) {
     }
 #endif
 
-#if __cplusplus >= 201103L || \
-    (defined(_MSC_VER) && _MSC_VER >= 1800)
-    // libdivdie::branchfree_divider<T>
-    template <typename T>
-    using branchfree_divider = divider<T, BRANCHFREE>;
-#endif
+// libdivdie::branchfree_divider<T>
+template <typename T>
+using branchfree_divider = divider<T, BRANCHFREE>;
 
 } // namespace libdivide