Modified: trunk/Source/WTF/ChangeLog (284849 => 284850)
--- trunk/Source/WTF/ChangeLog 2021-10-25 23:41:45 UTC (rev 284849)
+++ trunk/Source/WTF/ChangeLog 2021-10-26 00:16:10 UTC (rev 284850)
@@ -1,3 +1,18 @@
+2021-10-25 Yusuke Suzuki <[email protected]>
+
+ [WTF] Make Int128 operator* constexpr
+ https://bugs.webkit.org/show_bug.cgi?id=232270
+
+ Reviewed by Mark Lam.
+
+ We remove MSVC X64 (so, Windows only) switching in Int128 operator* since
+ it breaks constexpr-ness of operator*, which makes writing code difficult.
+ We can bring this kind of optimization back when C++20 std::is_constant_evaluated()
+ becomes available.
+
+ * wtf/Int128.h:
+ (WTF::operator*):
+
2021-10-25 Alex Christensen <[email protected]>
Use xpc_connection_copy_invalidation_reason where available for debugging daemon connection failures
Modified: trunk/Source/WTF/wtf/Int128.h (284849 => 284850)
--- trunk/Source/WTF/wtf/Int128.h 2021-10-25 23:41:45 UTC (rev 284849)
+++ trunk/Source/WTF/wtf/Int128.h 2021-10-26 00:16:10 UTC (rev 284850)
@@ -48,13 +48,9 @@
// builtin type. We need to make sure not to define operator wchar_t()
// alongside operator unsigned short() in these instances.
#define ABSL_INTERNAL_WCHAR_T __wchar_t
-#if CPU(X86_64)
-#include <intrin.h>
-#pragma intrinsic(_umul128)
-#endif // defined(_M_X64)
-#else // defined(_MSC_VER)
+#else
#define ABSL_INTERNAL_WCHAR_T wchar_t
-#endif // defined(_MSC_VER)
+#endif
namespace WTF {
@@ -515,7 +511,7 @@
constexpr UInt128Impl operator>>(UInt128Impl lhs, int amount);
constexpr UInt128Impl operator+(UInt128Impl lhs, UInt128Impl rhs);
constexpr UInt128Impl operator-(UInt128Impl lhs, UInt128Impl rhs);
-UInt128Impl operator*(UInt128Impl lhs, UInt128Impl rhs);
+constexpr UInt128Impl operator*(UInt128Impl lhs, UInt128Impl rhs);
WTF_EXPORT_PRIVATE UInt128Impl operator/(UInt128Impl lhs, UInt128Impl rhs);
WTF_EXPORT_PRIVATE UInt128Impl operator%(UInt128Impl lhs, UInt128Impl rhs);
@@ -812,14 +808,7 @@
lhs, rhs);
}
-inline UInt128Impl operator*(UInt128Impl lhs, UInt128Impl rhs) {
-#if COMPILER(MSVC) && CPU(X86_64)
- uint64_t carry;
- uint64_t low = _umul128(UInt128Low64(lhs), UInt128Low64(rhs), &carry);
- return MakeUInt128(UInt128Low64(lhs) * UInt128High64(rhs) +
- UInt128High64(lhs) * UInt128Low64(rhs) + carry,
- low);
-#else
+constexpr UInt128Impl operator*(UInt128Impl lhs, UInt128Impl rhs) {
uint64_t a32 = UInt128Low64(lhs) >> 32;
uint64_t a00 = UInt128Low64(lhs) & 0xffffffff;
uint64_t b32 = UInt128Low64(rhs) >> 32;
@@ -828,10 +817,9 @@
MakeUInt128(UInt128High64(lhs) * UInt128Low64(rhs) +
UInt128Low64(lhs) * UInt128High64(rhs) + a32 * b32,
a00 * b00);
- result += UInt128Impl(a32 * b00) << 32;
- result += UInt128Impl(a00 * b32) << 32;
- return result;
-#endif
+ UInt128Impl v1 = UInt128Impl(a32 * b00) << 32;
+ UInt128Impl v2 = UInt128Impl(a00 * b32) << 32;
+ return result + v1 + v2;
}
// Increment/decrement operators.
@@ -894,7 +882,7 @@
constexpr Int128Impl operator-(Int128Impl v);
constexpr Int128Impl operator+(Int128Impl lhs, Int128Impl rhs);
constexpr Int128Impl operator-(Int128Impl lhs, Int128Impl rhs);
-Int128Impl operator*(Int128Impl lhs, Int128Impl rhs);
+constexpr Int128Impl operator*(Int128Impl lhs, Int128Impl rhs);
WTF_EXPORT_PRIVATE Int128Impl operator/(Int128Impl lhs, Int128Impl rhs);
WTF_EXPORT_PRIVATE Int128Impl operator%(Int128Impl lhs, Int128Impl rhs);
constexpr Int128Impl operator|(Int128Impl lhs, Int128Impl rhs);
@@ -1192,7 +1180,7 @@
lhs, rhs);
}
-inline Int128Impl operator*(Int128Impl lhs, Int128Impl rhs) {
+constexpr Int128Impl operator*(Int128Impl lhs, Int128Impl rhs) {
return MakeInt128(
int128_internal::BitCastToSigned(UInt128High64(UInt128Impl(lhs) * rhs)),
UInt128Low64(UInt128Impl(lhs) * rhs));
