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Auf GitHub ansehenbasic properties of floor and ceiling function
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#76.438 geöffnet am 27. Dez. 2023
floating-pointgood first issuellvm:optimizationsmissed-optimization
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There are other formulas that hold, but I'll list the basic ones. https://alive2.llvm.org/ce/z/dQgZ84
If I understand correctly, these transformations require nnan flag.
Original functions:
#include <cmath>
bool src1(float x)
{
return std::floor(x) <= x;
}
bool src2(float x)
{
return x <= std::ceil(x);
}
bool src3(float x)
{
return std::ceil(x) == -std::floor(-x);
}
bool src4(float x)
{
return std::floor(x) == -std::ceil(-x);
}