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Fix Issue 24140 - Int128.opBinary [+-*/%&|^] with negative long arguments gives wrong answers

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This commit is contained in:
Nathan Sashihara 2023-09-11 17:32:49 -04:00 • committed by The Dlang Bot
parent d41877ba01
commit 932ce6d17c
1 changed files with 65 additions and 11 deletions
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72
std/int128.d
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@ -153,6 +153,7 @@ public struct Int128
{ {
return tst(this.data); return tst(this.data);
} }
} // @safe pure nothrow @nogc
/** Support binary arithmetic operators + - * / % & | ^ << >> >>> /** Support binary arithmetic operators + - * / % & | ^ << >> >>>
* Params: * Params:
@ -190,21 +191,49 @@ public struct Int128
} }
/// ditto /// ditto
Int128 opBinary(string op)(long op2) const Int128 opBinary(string op, Int)(const Int op2) const
if (op == "+" || op == "-" || if ((op == "+" || op == "-" ||
op == "*" || op == "/" || op == "%" || op == "*" || op == "/" || op == "%" ||
op == "&" || op == "|" || op == "^") op == "&" || op == "|" || op == "^") &&
is(Int : long) && __traits(isIntegral, Int))
{ {
static if (__traits(isUnsigned, Int))
return mixin("this " ~ op ~ " Int128(0, op2)"); return mixin("this " ~ op ~ " Int128(0, op2)");
else
return mixin("this " ~ op ~ " Int128((cast(long) op2) >> 63 , op2)");
} }
/// ditto /// ditto
Int128 opBinaryRight(string op)(long op2) const Int128 opBinary(string op, IntLike)(auto ref IntLike op2) const
if (op == "+" || op == "-" || if ((op == "+" || op == "-" ||
op == "*" || op == "/" || op == "%" || op == "*" || op == "/" || op == "%" ||
op == "&" || op == "|" || op == "^") op == "&" || op == "|" || op == "^") &&
is(IntLike : long) && !__traits(isIntegral, IntLike))
{ {
return opBinary!(op)(__traits(getMember, op2, __traits(getAliasThis, IntLike)[0]));
}
/// ditto
Int128 opBinaryRight(string op, Int)(const Int op2) const
if ((op == "+" || op == "-" ||
op == "*" || op == "/" || op == "%" ||
op == "&" || op == "|" || op == "^") &&
is(Int : long) && __traits(isIntegral, Int))
{
static if (__traits(isUnsigned, Int))
mixin("return Int128(0, op2) " ~ op ~ " this;"); mixin("return Int128(0, op2) " ~ op ~ " this;");
else
mixin("return Int128((cast(long) op2) >> 63, op2) " ~ op ~ " this;");
}
/// ditto
Int128 opBinaryRight(string op, IntLike)(auto ref IntLike op2) const
if ((op == "+" || op == "-" ||
op == "*" || op == "/" || op == "%" ||
op == "&" || op == "|" || op == "^") &&
is(IntLike : long) && !__traits(isIntegral, IntLike))
{
return opBinaryRight!(op)(__traits(getMember, op2, __traits(getAliasThis, IntLike)[0]));
} }
/// ditto /// ditto
@ -244,16 +273,16 @@ public struct Int128
} }
/// ditto /// ditto
ref Int128 opOpAssign(string op)(long op2) ref Int128 opOpAssign(string op, Int)(auto ref Int op2)
if (op == "+" || op == "-" || if ((op == "+" || op == "-" ||
op == "*" || op == "/" || op == "%" || op == "*" || op == "/" || op == "%" ||
op == "&" || op == "|" || op == "^" || op == "&" || op == "|" || op == "^" ||
op == "<<" || op == ">>" || op == ">>>") op == "<<" || op == ">>" || op == ">>>")
&& is(Int : long))
{ {
mixin("this = this " ~ op ~ " op2;"); mixin("this = this " ~ op ~ " op2;");
return this; return this;
} }
} // @safe pure nothrow @nogc
/** support arithmentic comparison operators < <= > >= /** support arithmentic comparison operators < <= > >=
* Params: op2 = right hand operand * Params: op2 = right hand operand
@ -411,4 +440,29 @@ unittest
auto w = Wrapped!ulong(ulong.max); auto w = Wrapped!ulong(ulong.max);
w.count++; // avoid invalid D-Scanner message that w could have been declared const w.count++; // avoid invalid D-Scanner message that w could have been declared const
assert(c < w); assert(c < w);
const zero = Int128(0L);
const one = Int128(1L);
const neg_one = Int128(-1L);
const neg_two = Int128(-2L);
// Correct result with ulong.max:
assert(zero + ulong.max == ulong.max);
assert(one * ulong.max == ulong.max);
assert((neg_one & ulong.max) == ulong.max);
assert((zero | ulong.max) == ulong.max);
assert((zero ^ ulong.max) == ulong.max);
// Correct result with negative arguments:
assert(zero + -1L == -1L);
assert(neg_two * -3L == 6L);
assert(neg_two / -2L == 1L);
assert(neg_two % -2L == 0L);
assert((neg_one & -1L) == -1L);
assert((zero | -1L) == -1L);
assert((zero ^ -1L) == -1L);
// Ensure alias this still works.
{
Int128 a = zero;
assert((a ^= w) == ulong.max);
}
assert((Wrapped!long(-1L) + zero) == -1L);
} }