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Avoid pointer aliasing for double/bits conversions.

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Instead use the llvm MathExtras.h functions for this, which use union
aliasing.
This commit is contained in:
Peter Johnson
2015-08-12 17:15:10 -07:00
parent c34ba968f1
commit e9618df1b5
2 changed files with 4 additions and 2 deletions
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3
src/WireEncoder.cpp
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@@ -12,6 +12,7 @@
#include <cstdlib>
#include <cstring>
#include "llvm/MathExtras.h"
#include "leb128.h"
using namespace nt;
@@ -30,7 +31,7 @@ WireEncoder::~WireEncoder() { std::free(m_start); }
void WireEncoder::WriteDouble(double val) {
Reserve(8);
// The highest performance way to do this, albeit non-portable.
std::uint64_t v = reinterpret_cast<uint64_t&>(val);
std::uint64_t v = llvm::DoubleToBits(val);
m_cur[7] = (char)(v & 0xff); v >>= 8;
m_cur[6] = (char)(v & 0xff); v >>= 8;
m_cur[5] = (char)(v & 0xff); v >>= 8;