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Optimize SWAP #527

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Merged
chfast merged 1 commit into from
Nov 25, 2022
Merged

Optimize SWAP #527

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17 changes: 16 additions & 1 deletion lib/evmone/instructions.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -802,7 +802,22 @@ template <int N>
inline void swap(StackTop stack) noexcept
{
static_assert(N >= 1 && N <= 16);
std::swap(stack.top(), stack[N]);

// The simple std::swap(stack.top(), stack[N]) is not used to workaround
// clang missed optimization: https://github.com/llvm/llvm-project/issues/59116
// TODO(clang): Check if #59116 bug fix has been released.

auto& a = stack[N];
auto& t = stack.top();
auto t0 = t[0];
auto t1 = t[1];
auto t2 = t[2];
auto t3 = t[3];
t = a;
a[0] = t0;
a[1] = t1;
a[2] = t2;
a[3] = t3;
}

template <size_t NumTopics>
Expand Down