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[libc][math] Remove UInt<128>::operation* specialization.

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Remove UInt<128>::operation* specialization since the generic implementation
works well enough:
https://quick-bench.com/q/Bz_J5HgAsz5m5V5Ze-X1fI77hPo

Reviewed By: michaelrj, sivachandra

Differential Revision: https://reviews.llvm.org/D138239
This commit is contained in:
Tue Ly
2022-11-17 17:49:16 -05:00
parent e205fc1836
commit 0d41b32b74
1 changed files with 0 additions and 34 deletions
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34
libc/src/__support/UInt.h
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@@ -493,40 +493,6 @@ template <size_t Bits> struct UInt {
const uint64_t *data() const { return val; }
};
template <>
constexpr UInt<128> UInt<128>::operator*(const UInt<128> &other) const {
// temp low covers bits 0-63, middle covers 32-95, high covers 64-127, and
// high overflow covers 96-159.
uint64_t temp_low = low(val[0]) * low(other[0]);
uint64_t temp_middle_1 = low(val[0]) * high(other[0]);
uint64_t temp_middle_2 = high(val[0]) * low(other[0]);
// temp_middle is split out so that overflows can be handled, but since
// but since the result will be truncated to 128 bits any overflow from here
// on doesn't matter.
uint64_t temp_high = low(val[0]) * low(other[1]) +
high(val[0]) * high(other[0]) +
low(val[1]) * low(other[0]);
uint64_t temp_high_overflow =
low(val[0]) * high(other[1]) + high(val[0]) * low(other[1]) +
low(val[1]) * high(other[0]) + high(val[1]) * low(other[0]);
// temp_low_middle has just the high 32 bits of low, as well as any
// overflow.
uint64_t temp_low_middle =
high(temp_low) + low(temp_middle_1) + low(temp_middle_2);
uint64_t new_low = low(temp_low) + (low(temp_low_middle) << 32);
uint64_t new_high = high(temp_low_middle) + high(temp_middle_1) +
high(temp_middle_2) + temp_high +
(low(temp_high_overflow) << 32);
UInt<128> result(0);
result[0] = new_low;
result[1] = new_high;
return result;
}
// Provides limits of UInt<128>.
template <> class numeric_limits<UInt<128>> {
public: